Question 1

A stone is moving on a rough level surface.It has 24 J of kinetic energy,and the friction force on it is a constant 0.50 N.What is the maximum distance it can slide?

Accepted Answer

A) 2.0 m 
B) 12 m 
C) 24 m 
D) 48 m 
A) 2.0 m 
B) 12 m 
C) 24 m 
D) 48 m

Question 2

An ideal spring stretches by 21.0 cm when a 135-N object is hung from it.If instead you hang a fish from this spring,what is the weight of a fish that would stretch the spring by

Accepted Answer

A) 199 N 
B) 91 N 
C) 145 N 
D) 279 N 
A) 199 N 
B) 91 N 
C) 145 N 
D) 279 N

Question 3

A 1000-kg car is moving at 15 km/h.If a 2000-kg truck has 23 times the kinetic energy of the car,how fast is the truck moving?

Accepted Answer

A) 51 km/h 
B) 72 km/h 
C) 61 km/h 
D) 41 km/h 
A) 51 km/h 
B) 72 km/h 
C) 61 km/h 
D) 41 km/h

Question 4

Three cars (car F,car G,and car H)are moving with the same speed and slam on their brakes.The most massive car is car F,and the least massive is car H.If the tires of all three cars have identical coefficients of kinetic friction with the road surface,which car travels the longest distance to skid to a stop?

Accepted Answer

A) They all travel the same distance in stopping. 
B) car F 
C) car G 
D) car H 
A) They all travel the same distance in stopping. 
B) car F 
C) car G 
D) car H

Question 5

A stone with a mass of 1.0 kg is tied to the end of a light string which keeps it moving in a circle with a constant speed of 4.0 m/s on a perfectly smooth horizontal tabletop.The radius of the path is 0.60 m.How much work does the tension in the string do on the stone as it makes one-half of a complete circle?

Accepted Answer

A) 100 J 
B) 3.8 J 
C) 0 J 
D) 40 J 
E) 80 J 
A) 100 J 
B) 3.8 J 
C) 0 J 
D) 40 J 
E) 80 J

Question 6

Two cyclists who weigh the same and have identical bicycles ride up the same mountain,both starting at the same time.Joe rides straight up the mountain,and Bob rides up the longer road that has a lower grade.Joe gets to the top before Bob.Ignoring friction and wind resistance,which one of the following statements is true?

Accepted Answer

A) The amount of work done by Joe is equal to the amount of work done by Bob,but the average power exerted by Joe is greater than that of Bob. 
B) The amount of work done by Joe is greater than the amount of work done by Bob,and the average power exerted by Joe is greater than that of Bob. 
C) Bob and Joe exerted the same amount of work,and the average power of each cyclist was also the same. 
D) The average power exerted by Bob and Joe was the same,but Joe exerted more work in getting there. 
A) The amount of work done by Joe is equal to the amount of work done by Bob,but the average power exerted by Joe is greater than that of Bob. 
B) The amount of work done by Joe is greater than the amount of work done by Bob,and the average power exerted by Joe is greater than that of Bob. 
C) Bob and Joe exerted the same amount of work,and the average power of each cyclist was also the same. 
D) The average power exerted by Bob and Joe was the same,but Joe exerted more work in getting there.

Question 7

Two objects,one of mass m and the other of mass 2m,are dropped from the top of a building.If there is no air resistance,when they hit the ground

Accepted Answer

A) both will have the same kinetic energy. 
B) the heavier one will have twice the kinetic energy of the lighter one. 
C) the heavier one will have four times the kinetic energy of the lighter one. 
D) the heavier one will have half the kinetic energy of the lighter one. 
E) the heavier one will have one-fourth the kinetic energy of the lighter one. 
A) both will have the same kinetic energy. 
B) the heavier one will have twice the kinetic energy of the lighter one. 
C) the heavier one will have four times the kinetic energy of the lighter one. 
D) the heavier one will have half the kinetic energy of the lighter one. 
E) the heavier one will have one-fourth the kinetic energy of the lighter one.

Question 8

If the force on an object is in the negative direction,the work it does on the object must be

Accepted Answer

A) negative. 
B) positive. 
C) The work could be either positive or negative,depending on the direction the object moves. 
A) negative. 
B) positive. 
C) The work could be either positive or negative,depending on the direction the object moves.

Question 9

The kinetic friction force that a horizontal surface exerts on a 60.0-kg object is 50.0 N.If the initial speed of the object is 25.0 m/s,what distance will it slide before coming to a stop?

Accepted Answer

A) 15.0 m 
B) 30.0 m 
C) 375 m 
D) 750 m 
A) 15.0 m 
B) 30.0 m 
C) 375 m 
D) 750 m

Question 10

A 1.0-kg object moving in a certain direction has a kinetic energy of 2.0 J.It hits a wall and comes back with half its original speed.What is the kinetic energy of this object at this point?

Accepted Answer

A) 2.0 J 
B) 1.0 J 
C) 0.50 J 
D) 0.25 J 
E) 4.0 J 
A) 2.0 J 
B) 1.0 J 
C) 0.50 J 
D) 0.25 J 
E) 4.0 J

Question 11

Person X pushes twice as hard against a stationary brick wall as person Y.Which one of the following statements is correct?

Accepted Answer

A) Both do positive work,but person X does four times the work of person Y. 
B) Both do positive work,but person X does twice the work of person Y. 
C) Both do the same amount of positive work. 
D) Both do zero work. 
E) Both do positive work,but person X does one-half the work of person Y. 
A) Both do positive work,but person X does four times the work of person Y. 
B) Both do positive work,but person X does twice the work of person Y. 
C) Both do the same amount of positive work. 
D) Both do zero work. 
E) Both do positive work,but person X does one-half the work of person Y.

Question 12

How much work would a child do while pulling a 12-kg wagon a distance of  
With a  
Force?

Accepted Answer

A) 95 J 
B) 52 J 
C) 67 J 
D) 109 J 
A) 95 J 
B) 52 J 
C) 67 J 
D) 109 J

Question 13

Jill does twice as much work as Jack does and in half the time.Jill's power output is

Accepted Answer

A) the same as Jack's power output. 
B) one-fourth as much as Jack's power output. 
C) one-half as much as Jack's power output. 
D) twice Jack's power output. 
E) four times Jack's power output. 
A) the same as Jack's power output. 
B) one-fourth as much as Jack's power output. 
C) one-half as much as Jack's power output. 
D) twice Jack's power output. 
E) four times Jack's power output.

Question 14

A person carries a 2.00-N pebble through the path shown in the figure,starting at point A and ending at point B.The total time from A to B is 6.75 min.How much work did gravity do on the rock between A and B?

Accepted Answer

A) 30.0 J 
B) -30.0 J 
C) -56.0 J 
D) 56.0 J 
E) -36.0 J 
A) 30.0 J 
B) -30.0 J 
C) -56.0 J 
D) 56.0 J 
E) -36.0 J

Question 15

It requires 0.30 kJ of work to fully drive a stake into the ground.If the average resistive force on the stake by the ground is  
How long is the stake?

Accepted Answer

A) 0.36 m 
B) 0.23 m 
C) 0.31 m 
D) 0.41 m 
A) 0.36 m 
B) 0.23 m 
C) 0.31 m 
D) 0.41 m

Exam 7: Work and Kinetic Energy

A stone is moving on a rough level surface.It has 24 J of kinetic energy,and the friction force on it is a constant 0.50 N.What is the maximum distance it can slide?

An ideal spring stretches by 21.0 cm when a 135-N object is hung from it.If instead you hang a fish from this spring,what is the weight of a fish that would stretch the spring by

A 1000-kg car is moving at 15 km/h.If a 2000-kg truck has 23 times the kinetic energy of the car,how fast is the truck moving?

Two objects,one of mass m and the other of mass 2m,are dropped from the top of a building.If there is no air resistance,when they hit the ground

If the force on an object is in the negative direction,the work it does on the object must be

The kinetic friction force that a horizontal surface exerts on a 60.0-kg object is 50.0 N.If the initial speed of the object is 25.0 m/s,what distance will it slide before coming to a stop?

A 1.0-kg object moving in a certain direction has a kinetic energy of 2.0 J.It hits a wall and comes back with half its original speed.What is the kinetic energy of this object at this point?

Person X pushes twice as hard against a stationary brick wall as person Y.Which one of the following statements is correct?

How much work would a child do while pulling a 12-kg wagon a distance of With a Force?

Jill does twice as much work as Jack does and in half the time.Jill's power output is

A person carries a 2.00-N pebble through the path shown in the figure,starting at point A and ending at point B.The total time from A to B is 6.75 min.How much work did gravity do on the rock between A and B?

It requires 0.30 kJ of work to fully drive a stake into the ground.If the average resistive force on the stake by the ground is How long is the stake?

Introduction to Physics

One-Dimensional Kinematics

Vectors in Physics

Two-Dimensional Kinematics

Newtons Laws of Motion

Applications of Newtons Laws

Potential Energy and Conservation of Energy

Linear Momentum and Collisions

Rotational Kinematics and Energy

Rotational Dynamics and Static Equilibrium

Gravity

Oscillations About Equilibrium

Waves and Sound

Fluids

Temperature and Heat

Phases and Phase Changes

The Laws of Thermodynamics

Electric Charges, Forces, and Fields

Electric Potential and Electric

Electric Current and Direct-Current Circuits

Magnetism

Magnetic Flux and Faradays Law of Induction

Alternating-Current Circuits

Electromagnetic Waves

Geometrical Optics

Optical Instruments

Physical Optics: Interference and Diffraction

Relativity

Quantum Physics

Atomic Physics

Nuclear Physics and Nuclear Radiation

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