# OpenStax College Physics Reading Quizzes

## Overview

Multiple Choice, Mulitple Select, and True/False Questions covering sections of OpenStax College Physics Text. These were designed to be for Reading Quizzes

For a copy of the answers, contact the author: Catherine Whiting at cwhiting@coloradomesa.edu

PHYS 111 Reading Quizzes Corresponding to OpenStax College Physics

(Sections 1.1, 1.2) + additional Scientific Notation note

Quiz 1

Which of the following statements best describes the difference between a scientific law and a theory. (There may be multiple correct answers)

- Laws and Theories are both supported by scientific evidence, however, a Law is a general statement, often expressed in a single equation, that describes phenomena in nature.
- Laws are general descriptions of nature supported by scientific evidence, while

Theories are educated guesses that have yet to be confirmed by observations and scientific evidence. - Theories are more complex than Laws in that they explain entire groups of related phenomena. Laws only describe a single action.

Which of the following is the correct set of SI units for the fundamental physical quantities of length, mass, and time:

- Length = meters, mass = grams, time = seconds

- Length = meters, mass = kilograms, time = seconds
- Length = miles, mass = grams, time = seconds
- Length = kilometers, mass = kilograms, time = seconds

What is the correct way to express the number 0.000078 in scientific notation?

- 78x10
^{5} - 7.8x10
^{4} - 0.78x10
^{-3} - 7.8x10
^{-4} - 7.8x10
^{-5}

(Sections 2.1-2.3)

Quiz 2

What is kinematics?

- The study of motion and its causes.
- The study of motion without regard to its causes.
- The study of forces and how they relate to the motion of an object.
- The study of forces and accelerations.

Which statement is true regarding the physics definitions of *displacement* and *distance*?

- The displacement of an object is always the same as the total distance travelled by that object.
- The displacement of an object is sometimes different than the total distance travelled by an object.
- The displacement of an object is always different than the total distance travelled by an object.
- The displacement of an object can be greater than the total distance travelled by an object.
- Displacement is a scalar quantity and distance traveled is a vector quantity.

Which of the following are vectors and which are scalars?

- Velocity of 10m/s due South Vector

- Temperature of 55F Scalar
- Distance of 20km Scalar
- Force of 500N towards the ground Vector
- Speed limit of 60mph Scalar

What is the difference between velocity and speed?

- Velocity is a scalar and speed is a vector.
- Velocity has a magnitude and direction but speed only has a magnitude.
- Velocity has a magnitude and direction but speed only has a direction.
- Velocity and speed are different names for the same concept.

(Section 2.4, up to section titled Instantaneous Acceleration)

Quiz 3

What is acceleration?

- A scalar quantity measuring the rate of change of the speed of an object.
- A scalar quantity measuring the rate of change of the velocity of an object.
- A vector quantity measuring the rate of change of the position of an object.
- A vector quantity measuring the rate of change of the speed of an object.
- A vector quantity measuring the rate of change of the velocity of an object.

Which of the following are true about deceleration?

- It is a negative acceleration.

- It occurs when an object slows down.
- When an object is decelerating, the sign of its acceleration is opposite to the direction of motion.
- An object decelerating always has its acceleration pointing to the left.

A car starts from rest and accelerates to a velocity of +10m/s in a time of 1s. What is the average acceleration of the car during that time?

- +10m/s
- +10m/s
^{2} - 0
- -10m/s
- -10m/s
^{2}

(Section 2.4 Instantaneous Acceleration until end of Section) + Section 2.6

Quiz 4

A train starts from rest, speeds up in the positive direction until it reaches a constant speed for a certain time. Then it slows down to a stop. (Assume that whenever the train accelerates it has a constant acceleration.). Which of the following represent the correct signs of the acceleration during the times of (speeding up, constant speed, slowing down)?

- (+,+,+)
- (+,0,+)
- (+,0,-)
- (-,0,+)
- (-,-,-)

An airplane lands on a runway traveling east. If we take the East direction to be positive, which of the following accurately describe the acceleration of the plane? (There might be multiple correct answers.)

- The plane has a negative acceleration.
- The plane is decelerating.
- The plane’s acceleration points East.
- The plane’s acceleration is in the same direction as the velocity of the plane.

True or False: The final step in solving any problem is to write down the final answer with units.

(Section 2.5)

Quiz 5

What is the important *assumption* that is made in deriving the kinematics equations?

- That the acceleration of the object is constant.
- That the velocity of the object is constant.
- That the change in velocity of an object is zero.
- That the acceleration of an object is zero.
- That the object always moves in a straight line.

Which of the following does the equation NOT tell us?

- The final velocity of an object depends on how large the acceleration is and how long it lasts
- If the acceleration of an object is zero, then the final velocity equals the initial velocity
- If the acceleration of an object is zero, then the object has a constant velocity.
- If the acceleration is negative, then the final velocity will always be negative.
- If the acceleration is negative, then the final velocity is less than the initial velocity.

A rocket accelerates at a rate of 20m/s^{2 }during launch. How long does it take to reach a velocity of 200m/s, if it starts from rest, and how far does it go in that time?

- t=10s, x=100m
- t=10s, x=1km
- t=20s, x=200m
- t=20s, x=1km
- t=20s, x=4km

(Section 2.8)

Quiz 6

What does the slope of a plot of *velocity vs. time* correspond to?

- Position
- Displacement
- Average velocity
- Instantaneous velocity
- Acceleration

In the equation v=v_{0}+at, what quantities correspond to properties of a straight line plotted on a graph of velocity vs time?

- a is the intercept and v0 is the slope
- a is the intercept and t is the slope
- v0 is the intercept and a is the slope
- v0 is the intercept and t is the slope
- t is the intercept and v0 is the slope

Suppose the plot of position vs. time of the motion of an object is a curve rather than a straight line. Which of the following can NOT be true?

- The velocity of the object changes.
- The slope of the position vs time plot is not constant.
- The velocity vs time plot will have a nonzero slope.
- The acceleration of the object is zero.

(Section 2.7)

Quiz 7

Which of the following is NOT true about objects in *free fall*?

- We assume there is no air resistance acting on them.
- We assume there is no friction acting on them.
- A heavier object in free fall will fall faster than a lighter object in free fall.
- They all fall with the same acceleration.

Which of the following best describe the acceleration due to gravity?

- A constant value always measured to be 9.8 m/s
^{2}, always defined to be negative. - A constant value always measured to be 9.8 m/s
^{2}, always directed downward. - It varies based on altitude and geographic features, but has an average value of 9.8m/s
^{2}, and is always defined to be negative. - It varies based on altitude and geographic features, but has an average value of 9.8m/s
^{2}, and is always directed downward.

Consider a rock thrown upward with a certain initial positive velocity. What will its plot of acceleration vs time look like?

- A parabola
- A positively sloped straight line
- A negatively sloped straight line
- A straight line at 0m/s
^{2} - A straight line at -9.8m/s
^{2}

(Sections 3.1, 3.2)

Quiz 8

A person walks to the store 4 blocks East and then 3 blocks North. What is the person’s total distance travelled and total displacement?

- Total distance = 7 blocks, Total displacement = 5 blocks
- Total distance = 7 blocks, Total displacement = 7 blocks
- Total distance = 5 blocks, Total displacement = 5 blocks
- Total distance = 5 blocks, Total displacement = 7 blocks
- Total distance = 7 blocks, Total displacement = 0 blocks

Which of the following are true regarding vectors?

- When drawn, the magnitude of a vector represents the length of the vector.
- Vectors are drawn such that the arrow points in the direction of the vector.
- The direction of the vector is specified by an angle.
- Vectors have components in a particular coordinate system.

Which of the following are correct about vector A?

- Its x component is given by
- Its y component is given by
- Its magnitude is given by A =
- The angle is given by
- The magnitude is given by A =

(Section 3.4)

Quiz 9

Which of the following are consequences of the fact that perpendicular motions are independent?

- The motion of a projectile can be broken up into horizontal and vertical motion separately.
- A ball dropped and a ball launched horizontally will hit the ground at the same time.
- The kinematics equations can be applied for the horizontal and vertical motion separately.
- The x and y motion of a projectile are dependent on each other.
- The only common variable between the horizontal and vertical motions of a projectile is time.

The arrows in the figure represent equally spaced intervals in time of what quantity of a projectile?

- The projectile’s displacement vector.
- The projectile’s horizontal velocity vector.
- The projectile’s vertical velocity vector.
- The projectile’s horizontal acceleration vector.
- The projectile’s vertical acceleration vector.

In which situation would it be most convenient to define a coordinate system in which down is the positive direction and why?

- When an object is thrown up because the initial velocity would be positive and the velocity of the object would stay positive, and g would be negative.
- When an object is thrown up because the initial velocity would be negative and the velocity of the object would stay negative, and g would be negative.
- When an object is thrown down because the initial velocity would be positive and the velocity of the object would stay positive, and g would be positive.
- When an object is thrown down because the initial velocity would be positive and the velocity of the object would stay positive, and g would be negative.
- When an object is thrown down because the initial velocity would be negative and the velocity of the object would stay negative, and g would be positive.

(Sections 3.2 and 3.3, covering vector addition)

Quiz 10

Which diagram correctly adds vectors A and B together?

- 1
- 2
- 3
- 1 and 2
- None of the diagrams are correct

How are two vectors subtracted from one another, i.e. how do we find A-B?

- We cannot subtract two vectors.
- We flip the arrow of the vector B to find the negative of B and add it to A.
- We rotate the vector B by 90 degrees and add it to A.

Which of the following is NOT one of the steps to add vectors together using analytical methods?

- Identify the x and y axes and then find the x and y components of each vector using trigonometry.
- Add the x components of the two vectors together and separately add the y components of the two vectors together.
- Add the magnitudes of the two vectors together.
- Find the magnitude of the total vector by using the Pythagorean theorem on the total x and y components.
- Find the direction of the total vector using trigonometry.

(Sections 4.1 and 4.2)

Quiz 11

Which of the following are true about a Force?

It could be a push or a pull.

It has a magnitude corresponding to the strength of the force.

It has a direction corresponding to the direction that the force is applied.

It is a vector quantity.

It can be represented by an arrow.

Which of the following are NOT a statement or consequence of Newton’s 1^{st} law?

A body at rest remains at rest unless acted on by a net external force.

A body in motion remains in motion at a constant velocity unless acted on by a net external force.

There must be a cause for there to be any change in velocity of an object.

If an object experiences an acceleration, there must be a net external force acting on it.

An object moving at a constant velocity will eventually slow and come to rest.

Which of the following properly describe inertia?

The tendency of an object to remain at rest or to remain in motion.

The mass of an object.

The amount of matter in an object.

The weight of an object.

(Section 4.3)

Quiz 12

Which of the following are meant by or a consequence of a change in motion?

A change in velocity.

An acceleration.

A net external force.

An internal force.

The same net force is applied to two objects, one with a large mass M and the other a small mass m. Choose the correct statement.

The acceleration of an object depends on the mass of an object, so mass M will experience a larger acceleration than mass m.

The acceleration of an object depends on the mass of an object, so mass m will experience a larger acceleration than mass M.

The acceleration of an object depends inversely on the mass of an object, so mass M will experience a larger acceleration than mass m.

The acceleration of an object depends inversely on the mass of an object, so mass m will experience a larger acceleration than mass M.

The acceleration of an object does not depend on the mass of an object, so both masses will experience the same acceleration.

What is the SI equivalent of a Newton, i.e. a unit of Force?

1N = 1kg m/s

1N = 1kg m/s^2

1N = 1kg m s

1N = 1kg m s^2

1N = 1kg m^2/s^2

If we define the downward direction as negative, what is the weight of a 3kg object?

+3N

+9.8N

+29.4N

-3N

-9.8N

-29.4N

(Sections 4.4 and 4.5 (Normal Force) only)

Quiz 13

Which of the following are restatements or consequences of Newton’s 3^{rd} Law?

For every force applied to an object there is an equal force applied back in the opposite direction.

A swimmer exerts a force on the pool wall and the pool wall exerts a force back on the swimmer.

Forces always occur in action-reaction pairs.

Equal and opposite forces always cancel.

A girl pushes on cart and does not experience any force by the cart.

What is a Normal force?

A name for the usual forces we experience in our everyday lives.

A force that is always applied parallel to an object.

A force that is applied to an object when it makes contact with a surface and is applied parallel to the surface.

A force that is applied to an object when it makes contact with a surface and is applied perpendicular to the surface.

A force that is applied to an object when it supports the weight of an object.

Section 4.5: Tension Force

Quiz 14

How is the Tension force of a rope applied to an object?

It is applied perpendicular to the rope and is equal to the weight of the object.

It is applied perpendicular to the rope and its value is determined by Newton’s 2^{nd} law.

It is applied parallel to the rope in the direction opposite the object and is equal to the weight of the object.

It is applied parallel to the rope in the direction opposite the object and its value is determined by Newton’s 2^{nd} Law.

It is applied parallel to the rope in the direction towards the object and is equal to the weight of the object.

It is applied parallel to the rope in the direction towards the object and its value is determined by Newton’s 2^{nd} Law.

How could you use tension in a rope to get a car out of the mud and why?

Tie a rope to the car and pull directly on the rope to maximize the tension in the rope, thus maximizing the force applied to the car.

Tie a rope to the car and a tree and pull on the middle of the rope parallel to the rope to maximize the tension in the rope, thus maximizing the force applied to the car.

Tie a rope to the car and a tree and pull on the middle of the rope perpendicular to the rope to maximize the tension in the rope, thus maximizing the force applied to the car.

Tie a rope to the car and a tree and pull on the middle of the rope parallel to the rope to minimize the tension in the rope, thus maximizing the force applied to the car.

Tie a rope to the car and a tree and pull on the middle of the rope parallel to the rope to minimize the tension in the rope, thus maximizing the force applied to the car.

Sections 4.6 and 4.7

Quiz 15

Which of the following are NOT drawn on a free-body diagram

Velocity of an object

Acceleration of an object

Internal Forces acting on an object

External Forces acting on an object

The system of interest.

If a system is accelerating in the horizontal direction, but not the vertical direction, how would you set up Newton’s 2^{nd}Law for this system?

Fnetx = max and Fnety =0

Fnetx=max and Fnety=-may

Fnetx=0 and Fnety=0

Fnetx=0 and Fnety=may

If you stand on a scale in an elevator, what will the scale read when you start accelerating up, in the positive direction?

It will read your normal weight because your weight doesn’t change.

It will read less than your normal weight because your acceleration is positive and will subtract from your weight.

It will read more than your normal weight because your acceleration is negative and will add to your weight.

It will read less than your normal weight because your acceleration is negative and will subtract from your weight.

It will read more than your normal weight because your acceleration is positive and will add to your normal weight.

A soccer player with a mass of 60kg starts from rest and accelerates forward, reaching a velocity of 4.00 m/s in 2 s. What was his average acceleration and what average force did he exert backward on the ground to achieve this acceleration?

A = 8m/s^2 and F=480N

A= 2m/s^2 and F=120N

A=8m/s^2 and F=120N

A=2m/s^2 and F=637N

A=2m/s^2 and F=757N

Section 5.1

Quiz 16

Which of the following statements are true regarding static and kinetic friction?

Fs<= mus N

Fk=muk N

Kinetic friction has a maximum and a minimum value.

Static friction will be equal and opposite to an applied force, up to a maximum limit

The magnitude of the kinetic friction force is nearly independent of the speed of the object moving on the surface.

What does a small coefficient of static friction between and object and a surface imply?

It will be easy to get the object to start moving along the surface.

It will be hard to get object to start moving along the surface.

It will be easy to keep the object moving along the surface.

It will be hard to keep the object moving along the surface.

Suppose the normal force acting on an object by a surface is 100N, and the coefficients of static and kinetic friction are 0.45 and 0.3, respectively. How much force would be required to get the object moving from rest, and how much force would be required to keep it moving?

ON to get it moving and 30N to keep it moving

45N to get it moving and 0N to keep it moving

30N to get it moving and 0N to keep it moving

30N to get it moving and 45N to keep it moving

45N to get it moving and 30N to keep it moving

Section 4.5 Example 4.5

Quiz 17

Which of the following free body diagrams most accurately reflects the skier in the figure?

A

A 62kg skier is skiing down a 15deg slope. Choosing a coordinate system with the x axis along the slope and the y axis perpendicular to the slope, what are the components of the skier’s weight W_x, and W_y?

W_x = 157N, W_y = 587N

W_x = 157N, W_y = -587N

W_x = 587N, W_y = 157N

W_x = 16N, W_y = 60N

W_x = 60N, W_y = 16N

Section 6.1

Quiz 18

What is the base unit used for measuring rotation angles?

Degrees

Revolutions

Radians

If an object makes half of one revolution around a circle, what is the rotation angle, Delta theta for this object? (There may be multiple correct answers.)

180 degrees

90 degrees

Pi radians

2pi radians

Pi revolutions

Which of the following are true for a rotating car tire? (There may be multiple correct answers.)

The linear speed of a point on the rim of the tire is the tangential speed.

The tangential speed of a point on the rim of the tire corresponds to the actual speed of the car.

For a fixed angular speed omega, if the car tire’s radius is increased, then the tangential speed of a point on the rim will decrease.

For a fixed car tire radius r, if the car increases its linear speed, then the tire’s angular speed omega will increase.

For a fixed car tire radius r, if the car tire’s angular speed increases, then the car must be moving faster.

Didn’t use:

A fly and an ant are sitting on a spinning record. The ant is at a distance r/2 from the center of the record and the fly is at the outer edge a distance r from the center.

Which of the following are true?

The fly and the ant have the same angular velocity, omega.

The fly will travel a greater distance than the ant.

The fly and ant will have the same rotation angle.

Sections 6.2 and 6.3

Quiz 19

What is centripetal acceleration? (There might be multiple correct answers.)

An acceleration resulting from the changing direction of an object moving in a circle.

An acceleration pointing away from the center of the circle the object is rotating about.

A_c=\frac{v^2}{r}

A_c=\omega r

What is the centripetal acceleration of a car moving at a speed of 10m/s around a curve of radius 200m?

0m/s^2

0.05m/s^2

0.5m/s^2

2000m/s^2

20000m/s^2

Which of the following is NOT an example of a centripetal force?

Tension in the rope on a tether ball

Force of Earth’s gravity on the Moon

Friction between roller skates and a rink floor

Banked roadway’s force on a car

All are examples of centripetal force

Quiz 20

(Section 7.1)

In order for work to be done, which of the following must happen?

There must be a force exerted.

The object must have a displacement in the direction of the force.

The force must be applied parallel to the direction of motion of the object.

The force must be applied perpendicular to the direction of motion of the object.

Energy is transferred.

A B

Which of the following are true about situations A and B in the figure above.

Work is done in both cases, because the man is applying a force to the briefcase.

Work is not done in Case A because the displacement is zero.

Work is done in Case B because a force is applied and there is a displacement.

Work is not done in Case B because the force is applied perpendicular to the displacement of the briefcase.

Work is not done in Case B because the force is applied at an angle of 90 degrees relative to the displacement so the cosine of theta is 0 and W = F cos theta d.

Can work done be negative?

No, there is no such thing as negative energy.

Yes, it means energy is removed.

Yes, it can occur when the force is applied opposite to the displacement.

Yes, it can occur when the angle between the force vector and the displacement is 180 degrees.

Which of the following are correct SI units for Work?

Joule

Nm

Kg m^2/s^2

Kg m/s^2

Kg m^2/s

Quiz 21

(Section 7.2)

Which of the following are true regarding translational kinetic energy?

KE=1/2mv^2

It represents a form of energy associated with the motion of an object

It can be negative.

It is measured in Joules.

The change in kinetic energy of an object equals the total work done on the object.

Quiz 22

(Section 7.3)

How much kinetic energy will an object moving at 100km/hr have compared to that same object moving at 50km/hr?

Moving at 100km/hr, it will have half the kinetic energy as when it is moving at 50km/hr

Moving at 100km/hr, it will have the same kinetic energy as when it is moving at 50km/hr

Moving at 100km/hr, it will have double the kinetic energy as when it is moving at 50km/hr

Moving at 100km/hr, it will have four times the kinetic energy as when it is moving at 50km/hr

According to the Work-Energy Theorem, what type of energy does the net Work give to a system?

Gravitational potential energy

Electric potential energy

Kinetic energy

It depends on the situation

What is gravitational potential energy? (Multiple correct answers.)

PE=mgh, where h is always the height of the object or system above the ground.

PE=mgh, where h is the change in height of the object or system.

Stored energy associated with the gravitational field of the Earth

Energy gained by an object when it is lifted to a height h above a reference point.

In Scenario A a person lifts a piano to the third floor by means of a rope. In Scenario B a person carries it up the stairs as shown. Which statement is true regarding the change in potential energy of the piano?

PE_A > PE_B

PE_A=PE_B

PE_A<PE_B

Reading Quiz 22

(Sections 5.3 (Hooke’s Law), Section 7.4 and 7.5)

A mass is attached to a spring with a spring constant k=100N/m is stretched by 2cm from its equilibrium position. How much force is applied to the mass by the spring and how much potential energy is stored by the mass?

F=200N, PE=200J

F=200N, PE=100J

F=200N, PE=0.02J

F=2N, PE=2J

F=2N, PE=0.02J

F=2N, PE=0.04J

Which of the following are true of conservative forces?

Gravity is an example of a conservative force.

Spring force is an example of a conservative force.

The work done by conservative forces on an object does not depend on the path of the object.

Conservative forces allow the system or object to store potential energy.

The work done by conservative forces on an object only depends on the initial and final positions of the object.

Which of the following are true of nonconservative forces?

Friction is an example of a nonconservative force.

The work done by nonconservative forces does not depend on the path of the object.

Nonconservative forces can change the total amount of mechanical energy of a system.

When nonconservative forces act on a system, they always reduce the mechanical energy of the system.

Reading Quiz 23

Section 7.6

Which of the following statements is NOT consistent with the law of conservation of energy?

Total energy is constant in any process.

Energy may change in form as long as the total energy remains the same.

Energy may be transferred from one system to another as long as the total energy of the systems remains the same.

An object always retains the same amount of energy.

What are some other forms of energy, besides Kinetic energy and gravitational or spring potential energy?

Electrical energy

Chemical energy

Radiation

Nuclear energy

Thermal energy

When you eat a big bowl of pasta before a race, what is the transformation of energy happening in this process?

Chemical energy in food transforms to thermal energy through your metabolism, which transforms to kinetic energy of your motion.

Light energy in food transforms to thermal energy through your metabolism, which transforms to spring potential energy.

Nuclear energy in food transforms to radiation energy through your metabolism, which transforms to thermal energy.

Electrical energy in food transforms to thermal energy though your metabolism, which transforms to kinetic energy of your motion.

Quiz 24

(Section 7.7) Power

Rank the following scenarios based on how much Power, in Watts, is used, from smallest to largest.

- A light bulb uses 100J of energy in 1 second.
- A car uses 10000J of energy to accelerate in 5 seconds.
- A girl uses 2000J of energy to climb a set of stairs in 10 seconds.

A, B, C

A, C, B

B, A, C

B, C, A

C, A, B

C, B, A

What is a kilowatt-hour?

A unit of energy

A unit of power

Neither a unit of energy nor power

Quiz 25

(Sections 8.1 and 8.2)

Rank the following from smallest momentum to largest.

- A car (m=1000kg) moving at a speed of 10m/s
- A boat (m=200kg) moving at a speed of 40m/s
- A tennis ball (m=0.03kg) moving at a speed of 300m/s

A, B, C

A, C, B

B, A, C

B, C, A

C, A, B

C, B, A

Why is Newton’s 2^{nd} Law written in terms of momentum more general than F=ma?

It applies to massive objects.

It applies for any time interval that the net force is applied.

It applies to systems where the mass can change.

It applies to situations where the force is not constant.

Why does an airbag reduce injury in a car crash?

The airbag reduces the time it takes to stop, thus reducing the force experienced.

The airbag increases the time it takes to stop, thus reducing the force experienced.

The airbag reduces the impulse experienced.

The airbag reduces the total change in momentum.

Quiz 26

(Sections 8.3, 8.4, 8.5, 8.6)

Under what condition(s) does the conservation of momentum principle apply?

When the system is isolated.

When the net external force on the system is zero.

When the total momentum is zero.

When the internal forces are zero.

Match the following types of collisions with their definitions.

A: Elastic collision. B: Inelastic collision, C: Perfectly inelastic collision

1: total kinetic energy is conserved

2: some kinetic energy is lost in the collision

3: the two objects stick together after the collision

1=A, 2=B, 3=C

1=A, 2=C, 3=B

1=B, 2=A, 3=C

1=B, 2=C, 3=A

1=C, 2=A, 3=B

1=C, 2=B, 3=A

When a goalie catches a hockey puck and the goalie with hockey puck in hand recoil backwards as a result, what type of collision is this?

Elastic

Inelastic

Perfectly inelastic

Quiz 27

Sections 9.1, 9.2

Why is Fnet = 0 a necessary but not sufficient condition for static equilibrium? (There may be more than one correct answer.)

If Fnet = 0 the object is not accelerating, but it could still be moving at a constant velocity.

If Fnet = 0 the object is not accelerating, but the forces could be applied to the object in such a way that the object experiences a rotational acceleration.

If Fnet = 0 the object is accelerating, and it could also be rotating.

Which of the following scenarios would make opening a door more effective.

Pushing on the door with a larger force .

Pushing on a door closer to the hinge where the door is attached to the wall.

Applying the pushing force perpendicular to the length of the door.

In the scenarios shown, assume the force F applied in all situations is the same magnitude.

Rank the scenarios from smallest to largest torque applied to the door.

What are the two conditions needed for an object to be in static equilibrium?

Fnet = 0 and ptot=0

Fext = 0 and Delta ptot = 0

Fnet = 0 and tnet = 0

Fext = 0 and tnet = 0

Quiz 28

(Section 9.4, 9.6?)

When solving static equilibrium situations, where should the pivot point be chosen?

It always needs to be applied at the actual pivot point.

It should be chosen in such a way to make the net torque zero.

It should be chosen at a location where there are unknown forces, because it will make the torque due to those forces zero.

It should be chosen at a location where there are unknown forces, because it will make the torques due to those forces cancel out.

Which of the following are true regarding torques in the human body?

To hold objects on our hand, our bicep muscle exerts much less force than the weight of the object, because it exerts a smaller torque.

To hold objects on our hand, our bicep muscle exerts much greater force than the weight of the object, because it is closer to our elbow joint than the hand, and therefore must exert a larger force in order to create the same torque as the weight of the object in our hand.

Bad posture is caused by our back muscles working to produce a counter torque due to the weight of the upper leaning away from the pivot point in the hips.

Good posture occurs when our upper body is aligned with the pivot point in our hips, such that no torque is exerted about our hips.

Quiz 29

(Sections 10.1, 10.2)

Which of the following statements correctly describe angular acceleration?

It is a change in velocity over time with units of rad/s

It is a change in angular velocity over time with units of rad/s^2

It is a change in tangential velocity with units of m/s^2

It is positive if angular velocity is positive and negative if angular velocity is negative.

It is positive if angular velocity increases and negative if angular velocity decreases.

It is positive if the object rotates counterclockwise at a constant angular speed.

Which of the following quantities is directly related to tangential acceleration?

Angular velocity

Angular Acceleration

Centripetal acceleration

Both centripetal and angular acceleration

Match the following translational quantity with its corresponding rotational variable.

(x, v, a)

Theta, omega, alpha

A fishing reel is wound up by a fisherman with an angular acceleration of 5rad/s^2 for 5 seconds. What is the final angular velocity of the reel if it started from rest?

1 rad/s

1 rad/s^2

25 rad/s

25 rad/s^2

62.5rad/s

Quiz 30

(Section 10.3)

What is the moment of inertia in rotational motion analogous to for linear translational motion?

Torque

Force

Mass

Acceleration

Displacement squared

What is the moment of inertia of a point mass (m=0.1kg) orbiting 0.2m from the center of rotation?

0.004kg*m^2

0.004kg*m

0.02kg*m^2

0.02kg*m

Which of the following correctly represent the relationship between torque, moment of inertia, and angular acceleration?

For a fixed amount of net torque, an object with a larger moment of inertia will result in a larger angular acceleration.

For a given object with a fixed moment of inertia, a larger torque applied will result in a larger angular acceleration.

If two objects have the same angular acceleration, the one with a larger moment of inertia must have a smaller net torque acting on it.

If two objects have the same net torque applied, the object with the larger angular acceleration will have more of its mass concentrated close to the axis of rotation.

Quiz 31

(Section 10.4)

How is rotational kinetic energy exactly analogous to translational kinetic energy? (There might be multiple correct answers)

It isn’t exactly analogous, since it doesn’t have the factor of ½ like translational kinetic energy.

Moment of inertia is the rotational analog of mass and angular speed is the rotational analog of speed.

I is like m and omega is like v.

A flywheel has a moment of inertia of 1000kgm^2 and is spinning at a rate of 20rad/s. What is the rotational kinetic energy of the flywheel?

In a race between three different soup cans, all with the same mass and radius, but different moments of inertia, as shown above, two of them roll without slipping and one of them slides without rolling, but with negligible friction. Which number represents the can with very little friction that slides without rolling?

1, because it will translate all of its potential energy into translational kinetic energy

3, because it will translate all of its potential energy into translational kinetic energy

3, because it has less kinetic energy, since it doesn’t roll

It cannot be determined without knowing the moments of inertia of the cans.

Quiz 32

(Section 10.5)

Rank the following objects according to their angular momentum, smallest to largest.

- A tennis ball (I=0.5kg*m^2) spinning at 200rad/s
- A baseball (I=0.9kg*m^2) spinning at 330rad/s
- A car tire (I=15kg*m^2) spinning at 15rad/s

1., 3., 2.

Under what condition is the angular momentum of a system conserved?

When the net force is zero.

When the net external force is zero.

When the net external torque is zero.

Which of the following are true regarding the Earth spinning on its axis?

It has a large angular momentum and very little external torque acting on it , which keeps it spinning once per day

.

The Earth once rotated slower but is gradually speeding up due to torques exerted by the moon.

The tides exert frictional torque on the Earth, gradually slowing is spin and increasing the length of the day.

Like a skater spinning, if the earth were to decrease in radius, its moment of inertia would decrease and therefore spin faster, due to conservation of angular momentum.

Quiz 33

(Sections 11.1-11.4)

A gas is considered a fluid.

True

False

What is the mass of a 0.01m^3 block of gold?

1932000kg

1932kg

193.2kg

88kg

0.1932kg

Which of the following are units of Pressure?

Pascal

Atmosphere (atm)

N/m

Millibar

Pounds per square inch (Psi)

Millimeters of Mercury (Mm Hg)

What is the pressure due to the weight of water in a container that is 0.15m deep?

9800Pa

1470Pa

1029Pa

9.8Pa

1.47Pa

An application of Pascal’s principle is Hydraulic systems, which consist of an enclosed fluid with input and output cylinders of different areas. Why are these useful?

A large input force on the small area cylinder will result in a small output force.

A large input force on the large area cylinder will result in a small output force.

A small input force on the small area cylinder will result in a large output force.

A small input force on the large area cylinder will result in a large output force.

Quiz 34

(Sections 11.6 and 11.7)

The pressure on a tire gauge reads 28psi. What is the absolute pressure in the tires?

38.7psi

28psi

13.3psi

Which of the following are true regarding the buoyant force?

It is a net upward force exerted on any object in a fluid.

It only acts on objects that float in a fluid.

It is equal to the weight of an object immersed in a fluid.

It is equal to the weight of the fluid that is displaced by the object.

What happens if the weight of an object immersed in a fluid is greater than the buoyant force?

It will float.

It will not move.

It will sink.

Cork has a density 1/5 the density of water. What fraction of the volume of the cork will be submerged in water when it floats?

1/5

½

3/5

4/5

Quiz 35

(Sections 13.1 and 13.3)

What is the SI Unit of Temperature?

Celsius

Fahrenheit

Kelvin

What are the Celsius and Kelvin temperatures of typical human body temperature: 98.6^{o}F?

37^{o}C and 310.15K

37^{o}C and 371.73K

209.48^{o}C and 310.15K

209.48^{o}C and 371.73K

209.48^{o}C and 482.63K

Which of the following statements are consistent with the ideal gas law?

If the volume and number of atoms in a gas is held constant, and the temperature increases, then the pressure will decrease.

If the number of atoms in a gas and the temperature of the gas is held constant, and the volume increases, then the pressure will decrease.

If the volume and temperature of a gas is held fixed, but the number of moles of the gas increases, then the pressure will increase.

If the number of moles of a gas and the pressure is held fixed, when the temperature increases, the volume will increase.

Quiz 36

(Sections 14.1 and 14.2)

Are heat and temperature the same?

Yes, heat is another way of describing temperature.

No, heat is a transfer of energy due to a temperature difference.

What factors determine how much heat is transferred to a system?

The change in temperature

The starting temperature of the system.

The mass of the system

The type of substance

The phase (solid, liquid, gas) of the substance.

Which of the following is NOT true about the specific heat of a substance?

It is the amount of heat needed to change the temperature of 1kg of mass by 1^{o}C

It has SI units are kcal/(kg ^{o}C)

It can depend on the temperature of the substance.

It is different for every substance and must generally be looked up in a table.

Its value is large for substances that require a lot of energy to raise the temperature.

How much heat is transferred to a 3kg pot of water in bringing it from 37^{o}C to 100^{ o}C?

62,800J

464,646

791,154J

1,255,800J

1,720,446J