Question 1

A certain battery charger uses 12 W of power. At 6.0 cents per kilowatt-hour, how much does it cost to charge batteries for a full day?

Accepted Answer

A)  1.4¢ 
B)  28¢ 
C)  1.7¢ 
D)  75¢ 
E)  2.3¢ 
A)  1.4¢ 
B)  28¢ 
C)  1.7¢ 
D)  75¢ 
E)  2.3¢

Question 2

How large a net force is required to accelerate a  1600-kg SUV from rest to a speed of  25 m/s in a distance of  200 m?

Accepted Answer

A)   0 N 
B)   2500 N 
C)   400 N 
D)   1600 N 
E)   200 N 
A)   0 N 
B)   2500 N 
C)   400 N 
D)   1600 N 
E)   200 N

Question 3

A roller coaster starts from rest at a height h at the left side of a loop-the-loop, as shown in the figure. It is not attached to the track in anyway, and there is no friction from the track or from air
Resistance. If the radius of the loop is R = 6.0 m, what is the minimum height h for which the roller
Coaster will not fall off the track at the top of the loop?

Accepted Answer

A)   15 m 
B)   12 m 
C)   18 m 
D)   21 m 
E)   8.5 m 
A)   15 m 
B)   12 m 
C)   18 m 
D)   21 m 
E)   8.5 m

Question 4

A very light ideal spring having a spring constant (force constant) of  8.2 N/cm is used to lift a 2.2-kg tool with an upward acceleration of $3.25 \mathrm {~m} / \mathrm { s } ^ { 2 }$

If the spring has negligible length when it us not stretched, how long is it while it is pulling the tool upward?

Accepted Answer

The answer of A very light ideal spring having a...

Question 5

In a museum exhibit of a simple pendulum, a very small but dense 6.0-kg ball swings from a very light 2.5-m wire. The ball is released from rest when the pendulum wire makes a 65° angle with
The vertical, and it swings in a circular arc with no appreciable friction or air resistance. What is the
Tension in the wire just as the ball swings through its lowest position?

Accepted Answer

A)  68 N 
B)  0 N 
C)  59 N 
D)  130 N 
E)  11 N 
A)  68 N 
B)  0 N 
C)  59 N 
D)  130 N 
E)  11 N

Question 6

A heavy stone and a light stone are released from rest in such away that they both have the same amount of gravitational potential energy just as they are released. Air resistance is negligibly small.
Which of the following statements about these stones are correct? (There could be more than one
Correct choice.)

Accepted Answer

A)  Just as it reaches the ground, the light stone is traveling faster than the heavy stone. 
B)  The stones both have the same kinetic energy just as they reach the ground. 
C)  The stones must have been released from the same height. 
D)  The stones both have the same speed just as they reach the ground. 
E)  The initial height of the light stone is greater than the initial height of the heavy stone. 
A)  Just as it reaches the ground, the light stone is traveling faster than the heavy stone. 
B)  The stones both have the same kinetic energy just as they reach the ground. 
C)  The stones must have been released from the same height. 
D)  The stones both have the same speed just as they reach the ground. 
E)  The initial height of the light stone is greater than the initial height of the heavy stone.

Question 7

A 60-kg skier pushes off the top of a frictionless hill with an initial speed of 4.0 m/s. How fast will she be moving after dropping 10 m in elevation? Air resistance is negligible.

Accepted Answer

A)  10 m/s 
B)  15 m/s 
C)  0.15 km/s 
D)  0.20 km/s 
E)  49 m/s 
A)  10 m/s 
B)  15 m/s 
C)  0.15 km/s 
D)  0.20 km/s 
E)  49 m/s

Question 8

As shown in the figure, a 1.45-kg block is held in place against the spring by a 21-N horizontal external force. The external force is removed, and the block is projected with a velocity  $v _ { 1 }$=1.2 m/s as it separates from the spring. The block descends a ramp and has a velocity $v _ { 2 } = 2.1 \mathrm {~m} / \mathrm { s }$ at the bottom. The track is frictionless between points  A  and  B . The block enters a rough section at  B , extending to E. The coefficient of kinetic friction between the block and the rough surface is  0.29 . The velocity of the block is $v _ { 3 } = 1.4 \mathrm {~m} / \mathrm { s }$ at C. The block moves on to D, where it stops. How much work is done by friction between points  B  and  C  ?

Accepted Answer

A)   -7.0 J 
B)   -1.8 J 
C)   -14 J 
D)   -6.4 J 
E)   -3.6 J 
A)   -7.0 J 
B)   -1.8 J 
C)   -14 J 
D)   -6.4 J 
E)   -3.6 J

Question 9

Two identical grasshoppers jump into the air with the same initial speed and experience no air resistance. Grasshopper A goes straight up, but grasshopper B goes up at a 66° angle above the
Horizontal. Which of the following statements about these grasshoppers are correct? (There could
Be more than one correct choice.)

Accepted Answer

A)  At their highest point, both of them have the same amount of gravitational potential energy. 
B)  At their highest point, both of them have the same amount of mechanical energy. 
C)  At their highest point, grasshopper A has more gravitational potential energy than grasshopper B. 
D)  At their highest point, both of them have the same amount of kinetic energy. 
E)  At their highest point, grasshopper B is moving faster than grasshopper A. 
A)  At their highest point, both of them have the same amount of gravitational potential energy. 
B)  At their highest point, both of them have the same amount of mechanical energy. 
C)  At their highest point, grasshopper A has more gravitational potential energy than grasshopper B. 
D)  At their highest point, both of them have the same amount of kinetic energy. 
E)  At their highest point, grasshopper B is moving faster than grasshopper A.

Question 10

A 10-kg mass, hung by an ideal spring, causes the spring to stretch 2.0 cm. What is the spring constant (force constant) for this spring?

Accepted Answer

A)   0.0020 N/cm 
B)   0.20 N/cm 
C)   5.0 N/cm 
D)   49 N/cm 
E)   20 N/cm 
A)   0.0020 N/cm 
B)   0.20 N/cm 
C)   5.0 N/cm 
D)   49 N/cm 
E)   20 N/cm

Question 11

A heavy sled and a light sled, both moving horizontally with the same speed, suddenly slide onto a rough patch of snow and eventually come to a stop. The coefficient of kinetic friction between the
Sleds and the rough snow is the same for both of them. Which of the following statements about
These sleds are correct? (There could be more than one correct choice.)

Accepted Answer

A)  The friction from the snow will do the same amount of work on both sleds. 
B)  Both sleds will slide the same distance on the rough snow before stopping. 
C)  The heavy sled will slide farther on the rough snow than the light sled. 
D)  The light sled will slide farther on the rough snow than the heavy sled. 
E)  The friction from the snow will do more negative work on the heavy sled than on the light sled. 
A)  The friction from the snow will do the same amount of work on both sleds. 
B)  Both sleds will slide the same distance on the rough snow before stopping. 
C)  The heavy sled will slide farther on the rough snow than the light sled. 
D)  The light sled will slide farther on the rough snow than the heavy sled. 
E)  The friction from the snow will do more negative work on the heavy sled than on the light sled.

Question 12

A child pulls on a wagon with a force of 75 N. If the wagon moves a total of 42 m in 3.1 min, what is the average power delivered by the child?

Accepted Answer

A)  17 W 
B)  21 W 
C)  26 W 
D)  22 W 
A)  17 W 
B)  21 W 
C)  26 W 
D)  22 W

Question 13

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

Question 14

A heavy dart and a light dart are launched vertically by identical ideal springs. Both springs were initially compressed by the same amount. There is no significant air resistance. Which of the
Following statements about these darts are correct? (There could be more than one correct choice.)

Accepted Answer

A)  The light dart goes higher than the heavy dart. 
B)  At the maximum height, both darts have the same gravitational potential energy. 
C)  Both darts began moving upward with the same initial speed. 
D)  The heavy dart goes higher than the light dart. 
E)  Both darts reach the same maximum height. 
A)  The light dart goes higher than the heavy dart. 
B)  At the maximum height, both darts have the same gravitational potential energy. 
C)  Both darts began moving upward with the same initial speed. 
D)  The heavy dart goes higher than the light dart. 
E)  Both darts reach the same maximum height.

Question 15

Three cars (car L, car M, and car N) are moving with the same speed and slam on their brakes. The most massive car is car L, and the least massive is car N. If the tires of all three cars have identical
Coefficients of kinetic friction with the road surface, for which car is the amount of work done by
Friction in stopping it the greatest?

Accepted Answer

A)  The amount of work done by friction is the same for all cars. 
B)  Car N 
C)  Car M 
D)  Car L 
A)  The amount of work done by friction is the same for all cars. 
B)  Car N 
C)  Car M 
D)  Car L

Question 16

A roller coaster starting from rest descends 35 meters in its initial drop and then rises 23
meters when it goes over the first hill, which has a circular shape over the top. If a
passenger at the top of the hill feels an apparent weight equal to one-half of her normal
weight, what is the radius of curvature of the first hill? Neglect any frictional losses.

Accepted Answer

The answer of A roller coaster starting from rest descends...

Question 17

A traveler pulls on a suitcase strap at an angl $36 ^ { \circ }$ above the horizontal. If 555 J of work are done by the strap while moving the suitcase a horizontal distance of 15 m, what is the tension in the
Strap?

Accepted Answer

A)  46 N 
B)  52 N 
C)  37 N 
D)  56 N 
A)  46 N 
B)  52 N 
C)  37 N 
D)  56 N

Question 18

The figure shows two crates, each of mass  m=24 kg, that are connected by a very light wire. The coefficient of kinetic friction between the crate on the inclined surface and the surface itself is  0.31 . Find the speed of the crates after they have moved  1.6 m starting from rest.

Accepted Answer

The answer of The figure shows two crates, each of...

Question 19

If 4.0 J of work are performed in stretching an ideal spring with a spring constant (force constant) of 2500 N/m, by what distance is the spring stretched?

Accepted Answer

A)  5.7 cm 
B)  3.2 cm 
C)  3.2 m 
D)  0.3 cm 
E)  5.7 m 
A)  5.7 cm 
B)  3.2 cm 
C)  3.2 m 
D)  0.3 cm 
E)  5.7 m

Question 20

The net force that an animal exerts on a large piece of fruit it has found is observed and is shown in the graph in the figure. If the force is parallel to the motion of the fruit, how much work did the animal do during the encounter?

Accepted Answer

A)   50 J 
B)   0 J 
C)   22 J 
D)   25 J 
E)   12.5 J 
A)   50 J 
B)   0 J 
C)   22 J 
D)   25 J 
E)   12.5 J

Exam 6: Work and Energy

A certain battery charger uses 12 W of power. At 6.0 cents per kilowatt-hour, how much does it cost to charge batteries for a full day?

How large a net force is required to accelerate a 1600-kg SUV from rest to a speed of 25 m/s in a distance of 200 m?

A 60-kg skier pushes off the top of a frictionless hill with an initial speed of 4.0 m/s. How fast will she be moving after dropping 10 m in elevation? Air resistance is negligible.

A 10-kg mass, hung by an ideal spring, causes the spring to stretch 2.0 cm. What is the spring constant (force constant) for this spring?

A child pulls on a wagon with a force of 75 N. If the wagon moves a total of 42 m in 3.1 min, what is the average power delivered by the child?

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 heavy dart and a light dart are launched vertically by identical ideal springs. Both springs were initially compressed by the same amount. There is no significant air resistance. Which of the Following statements about these darts are correct? (There could be more than one correct choice.)

A traveler pulls on a suitcase strap at an angl 36∘36 ^ { \circ }36∘ above the horizontal. If 555 J of work are done by the strap while moving the suitcase a horizontal distance of 15 m, what is the tension in the Strap?

The figure shows two crates, each of mass m=24 kg, that are connected by a very light wire. The coefficient of kinetic friction between the crate on the inclined surface and the surface itself is 0.31 . Find the speed of the crates after they have moved 1.6 m starting from rest.

If 4.0 J of work are performed in stretching an ideal spring with a spring constant (force constant) of 2500 N/m, by what distance is the spring stretched?

The net force that an animal exerts on a large piece of fruit it has found is observed and is shown in the graph in the figure. If the force is parallel to the motion of the fruit, how much work did the animal do during the encounter?

Introduction, Measurement, Estimating

Describing Motion: Kinematics in One Dimension

Kinematics in Two Dimensions; Vectors

Dynamics: Newtons Laws of Motion

Circular Motion; Gravitation

Linear Momentum

Rotational Motion

Static Equilibrium; Elasticity and Fracture

Fluids

Oscillations and Waves

Sound

Temperature and Kinetic Theory

Heat

The Laws of Thermodynamics

Electric Charge and Electric Field

Electric Potential

Electric Currents

Dc Circuits

Magnetism

Electromagnetic Induction and Faradays Law

Electromagnetic Waves

Light: Geometric Optics

The Wave Nature of Light

Optical Instruments

The Special Theory of Relativity

Early Quantum Theory and Models of the Atom

Quantum Mechanics of Atoms

Molecules and Solids

Nuclear Physics and Radioactivity

Nuclear Energy; Effects and Uses of Radiation

Elementary Particles

Astrophysics and Cosmology

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A traveler pulls on a suitcase strap at an angl $36 ^ { \circ }$ above the horizontal. If 555 J of work are done by the strap while moving the suitcase a horizontal distance of 15 m, what is the tension in the Strap?