Question 1

If two nonzero vectors point in the same direction, their dot product must be zero.

Accepted Answer

A)  True 
B)  False 
A)  True 
B)  False B

Question 2

The work performed as a function of time for a process is given by   where   What is the instantaneous power output at

Accepted Answer

A)  99 W 
B)  69 W 
C)  139 W 
D)  208 W 
A)  99 W 
B)  69 W 
C)  139 W 
D)  208 W A

Question 3

An object is acted upon by a force that represented by the force vs. position graph in the figure. What is the work done as the object moves
(a) from 4 m to 6 m?
(b) from 6 m to 12 m?

Accepted Answer

(a) 20 J (b) 30 J

Question 4

You slam on the brakes of your car in a panic, and skid a certain distance on a straight, level road. If you had been traveling twice as fast, what distance would the car have skidded, under identical conditions?

Accepted Answer

A)  It would have skidded 4 times farther. 
B)  It would have skidded 2 times farther. 
C)  It would have skidded   times farther. 
D)  It would have skidded 1/   times farther. 
E)  It would have skidded 1/2 as far. 
A)  It would have skidded 4 times farther. 
B)  It would have skidded 2 times farther. 
C)  It would have skidded   times farther. 
D)  It would have skidded 1/   times farther. 
E)  It would have skidded 1/2 as far.

Question 5

The angle between vector   = 2.00   + 3.00   and vector   is   The scalar product of vectors   and   is 3.00. If the x component of vector   is positive, what is vector   .

Accepted Answer

A)    
B)    
C)    
D)    
E)    
A)    
B)    
C)    
D)    
E)

Question 6

The force on a 3.00-kg object as a function of position is shown in the figure. If an object is moving at 2.50 m/s when it is located at x = 2.00 m, what will its speed be when it reaches x = 8.00 m? (Assume that the numbers on the graph are accurate to 3 significant figures.)

Accepted Answer

A)  3.25 m/s 
B)  3.70 m/s 
C)  4.10 m/s 
D)  2.90 m/s 
E)  4.50 m/s 
A)  3.25 m/s 
B)  3.70 m/s 
C)  4.10 m/s 
D)  2.90 m/s 
E)  4.50 m/s

Question 7

A 1000 kg car experiences a net force of 9500 N while decelerating from 30.0 m/s to 23.4 m/s. How far does it travel while slowing down?

Accepted Answer

A)  18.5 m 
B)  17.4 m 
C)  20.2 m 
D)  21.9 m 
A)  18.5 m 
B)  17.4 m 
C)  20.2 m 
D)  21.9 m

Question 8

It requires 49 J of work to stretch an ideal very light spring from a length of 1.4 m to a length of 2.9 m. What is the value of the spring constant of this spring?

Accepted Answer

A)  15 N/m 
B)  44 N/m 
C)  29 N/m 
D)  22 N/m 
A)  15 N/m 
B)  44 N/m 
C)  29 N/m 
D)  22 N/m

Question 9

A stock person at the local grocery store has a job consisting of the following five segments: (1) picking up boxes of tomatoes from the stockroom floor
(2) accelerating to a comfortable speed
(3) carrying the boxes to the tomato display at constant speed
(4) decelerating to a stop
(5) lowering the boxes slowly to the floor.
During which of the five segments of the job does the stock person do positive work on the boxes?

Accepted Answer

A)  (1) and (5) 
B)  (1) only 
C)  (1), (2), (4), and (5) 
D)  (1) and (2) 
E)  (2) and (3) 
A)  (1) and (5) 
B)  (1) only 
C)  (1), (2), (4), and (5) 
D)  (1) and (2) 
E)  (2) and (3)

Question 10

A force   = 12 N   - 10 N   acts on an object. How much work does this force do as the object moves from the origin to the point

Accepted Answer

A)  46 J 
B)  266 J 
C)  37 J 
D)  62 J 
A)  46 J 
B)  266 J 
C)  37 J 
D)  62 J

Question 11

A force F = bx3 acts in the x direction, where the value of b is 3.7 N/m3. How much work is done by this force in moving an object from   to

Accepted Answer

A)  42 J 
B)  13 J 
C)  50 J 
D)  57 J 
A)  42 J 
B)  13 J 
C)  50 J 
D)  57 J

Question 12

A person pushes horizontally on a heavy box and slides it across the level floor at constant velocity. The person pushes with a 60.0 N force for the first   at which time he begins to tire. The force he exerts then starts to decrease linearly from 60.0 N to 0.00 N across the remaining   How much total work did the person do on the box?

Accepted Answer

A)  619 J 
B)  826 J 
C)  495 J 
D)  925 J 
A)  619 J 
B)  826 J 
C)  495 J 
D)  925 J

Question 13

A 3.00-kg ball swings rapidly in a complete vertical circle of radius 2.00 m by a light string that is fixed at one end. The ball moves so fast that the string is always taut and perpendicular to the velocity of the ball. As the ball swings from its lowest point to its highest point

Accepted Answer

A)  the work done on it by gravity and the work done on it by the tension in the string are both equal to -118 J. 
B)  the work done on it by gravity is -118 J and the work done on it by the tension in the string is +118 J. 
C)  the work done on it by gravity is +118 J and the work done on it by the tension in the string is -118 J. 
D)  the work done on it by gravity is -118 J and the work done on it by the tension in the string is zero. 
E)  the work done on it by gravity and the work done on it by the tension in the string are both equal to zero. 
A)  the work done on it by gravity and the work done on it by the tension in the string are both equal to -118 J. 
B)  the work done on it by gravity is -118 J and the work done on it by the tension in the string is +118 J. 
C)  the work done on it by gravity is +118 J and the work done on it by the tension in the string is -118 J. 
D)  the work done on it by gravity is -118 J and the work done on it by the tension in the string is zero. 
E)  the work done on it by gravity and the work done on it by the tension in the string are both equal to zero.

Question 14

Determine the scalar product of   = 6.0   + 4.0   - 2.0   and   = 5.0   - 6.0   - 3.0   .

Accepted Answer

A)  30   + 24   + 6   
B)  30   - 24   + 6   
C)  12 
D)  60 
E)  undefined 
A)  30   + 24   + 6   
B)  30   - 24   + 6   
C)  12 
D)  60 
E)  undefined

Question 15

In the figure, a constant external force P = 160 N is applied to a 20.0-kg box, which is on a rough horizontal surface. While the force pushes the box a distance of 8.00 m, the speed changes from 0.500 m/s to 2.60 m/s. The work done by friction during this process is closest to

Accepted Answer

A)  -1040 J. 
B)  +1110 J. 
C)  +1170 J. 
D)  +1040 J. 
E)  -1170 J. 
A)  -1040 J. 
B)  +1110 J. 
C)  +1170 J. 
D)  +1040 J. 
E)  -1170 J.

Question 16

A graph of the force on an object as a function of its position is shown in the figure. Determine the amount of work done by this force on an object that moves from x = 1.0 m to x = 6.0 m. (Assume an accuracy of 2 significant figures for the numbers on the graph.)

Accepted Answer

A)  26 J 
B)  29 J 
C)  22 J 
D)  35 J 
E)  27 J 
A)  26 J 
B)  29 J 
C)  22 J 
D)  35 J 
E)  27 J

Question 17

Consider a plot of the displacement (x) as a function of the applied force (F) for an ideal elastic spring. The slope of the curve would be

Accepted Answer

A)  the spring constant. 
B)  the reciprocal of the spring constant. 
C)  the acceleration due to gravity. 
D)  the reciprocal of the acceleration of gravity. 
E)  the mass of the object attached to the spring. 
A)  the spring constant. 
B)  the reciprocal of the spring constant. 
C)  the acceleration due to gravity. 
D)  the reciprocal of the acceleration of gravity. 
E)  the mass of the object attached to the spring.

Question 18

A 4.0-kg object is moving with speed 2.0 m/s. A 1.0-kg object is moving with speed 4.0 m/s. Both objects encounter the same constant braking force, and are brought to rest. Which object travels the greater distance before stopping?

Accepted Answer

A)  the 4.0-kg object 
B)  the 1.0-kg object 
C)  Both objects travel the same distance. 
D)  It is impossible to know without knowing how long each force acts. 
A)  the 4.0-kg object 
B)  the 1.0-kg object 
C)  Both objects travel the same distance. 
D)  It is impossible to know without knowing how long each force acts.

Question 19

Block A (0.40 kg) and block B (0.30 kg) are on a frictionless table (see figure). Spring 1 connects block A to a frictionless peg at 0 and spring 2 connects block A and block B. When the blocks are in uniform circular motion about 0, the springs have lengths of 0.60 m and 0.40 m, as shown. The springs are ideal and massless, and the linear speed of block B is 2.0 m/s. If the distance that spring 2 stretches is 0.060 m, the spring constant of spring 2 is closest to

Accepted Answer

A)  18 N/m. 
B)  20 N/m. 
C)  22 N/m. 
D)  24 N/m. 
E)  26 N/m. 
A)  18 N/m. 
B)  20 N/m. 
C)  22 N/m. 
D)  24 N/m. 
E)  26 N/m.

Question 20

Find the net work done by friction on the body of a snake slithering in a complete circle of   radius. The coefficient of friction between the ground and the snake is 0.25, and the snake's weight is

Accepted Answer

A)  -330 J 
B)  0 J 
C)  -3300 J 
D)  -670 J 
A)  -330 J 
B)  0 J 
C)  -3300 J 
D)  -670 J

Exam 9: Work and Kinetic Energy

If two nonzero vectors point in the same direction, their dot product must be zero.

The work performed as a function of time for a process is given by where What is the instantaneous power output at

An object is acted upon by a force that represented by the force vs. position graph in the figure. What is the work done as the object moves (a) from 4 m to 6 m? (b) from 6 m to 12 m?

You slam on the brakes of your car in a panic, and skid a certain distance on a straight, level road. If you had been traveling twice as fast, what distance would the car have skidded, under identical conditions?

The angle between vector = 2.00 + 3.00 and vector is The scalar product of vectors and is 3.00. If the x component of vector is positive, what is vector .

The force on a 3.00-kg object as a function of position is shown in the figure. If an object is moving at 2.50 m/s when it is located at x = 2.00 m, what will its speed be when it reaches x = 8.00 m? (Assume that the numbers on the graph are accurate to 3 significant figures.)

A 1000 kg car experiences a net force of 9500 N while decelerating from 30.0 m/s to 23.4 m/s. How far does it travel while slowing down?

It requires 49 J of work to stretch an ideal very light spring from a length of 1.4 m to a length of 2.9 m. What is the value of the spring constant of this spring?

A force = 12 N - 10 N acts on an object. How much work does this force do as the object moves from the origin to the point

A force F = bx3 acts in the x direction, where the value of b is 3.7 N/m3. How much work is done by this force in moving an object from to

A 3.00-kg ball swings rapidly in a complete vertical circle of radius 2.00 m by a light string that is fixed at one end. The ball moves so fast that the string is always taut and perpendicular to the velocity of the ball. As the ball swings from its lowest point to its highest point

Determine the scalar product of = 6.0 + 4.0 - 2.0 and = 5.0 - 6.0 - 3.0 .

In the figure, a constant external force P = 160 N is applied to a 20.0-kg box, which is on a rough horizontal surface. While the force pushes the box a distance of 8.00 m, the speed changes from 0.500 m/s to 2.60 m/s. The work done by friction during this process is closest to

A graph of the force on an object as a function of its position is shown in the figure. Determine the amount of work done by this force on an object that moves from x = 1.0 m to x = 6.0 m. (Assume an accuracy of 2 significant figures for the numbers on the graph.)

Consider a plot of the displacement (x) as a function of the applied force (F) for an ideal elastic spring. The slope of the curve would be

A 4.0-kg object is moving with speed 2.0 m/s. A 1.0-kg object is moving with speed 4.0 m/s. Both objects encounter the same constant braking force, and are brought to rest. Which object travels the greater distance before stopping?

Find the net work done by friction on the body of a snake slithering in a complete circle of radius. The coefficient of friction between the ground and the snake is 0.25, and the snake's weight is

Concepts of Motion

Kinematics in One Dimension

Vectors and Coordinate Systems

Kinematics in Two Dimensions

Force and Motion

Dynamics I: Motion Along a Line

Newtons Third Law

Dynamics Ii: Motion in a Plane

Interactions and Potential Energy

Impulse and Momentum

Rotation of a Rigid Body

Newtons Theory of Gravity

Fluids and Elasticity

Oscillations

Traveling Waves

Superposition

A Macroscopic Description of Matter

Work, Heat, and the First Law of Thermodynamics

The Micromacro Connection

Heat Engines and Refrigerators

Electric Charges and Forces

The Electric Field

Gausss Law

The Electric Potential

Potential and Field

Current and Resistance

Fundamentals of Circuits

The Magnetic Field

Electromagnetic Induction

Electromagnetic Fields and Waves

Ac Circuits

Wave Optics

Ray Optics

Optical Instruments

Relativity

The Foundations of Modern Physics

Quantization

Wave Functions and Uncertainty

One-Dimensional Quantum Mechanics

Atomic Physics

Nuclear Physics

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A force F = bx³ acts in the x direction, where the value of b is 3.7 N/m³. How much work is done by this force in moving an object from to