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

Question 2

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

Question 3

A 1-kg ball is released from a height of 6 m,and a 2-kg ball is released from a height of 3 m.Air resistance is negligible as they fall.Which of the following statements about these balls are correct? (There could be more than one correct choice. )

Accepted Answer

A) As they reach the ground,the 1-kg ball will have more kinetic energy than the 2-kg ball because it was dropped from a greater height. 
B) As they reach the ground,the 1-kg ball will be moving faster than the 2-kg ball. 
C) Both balls will reach the ground with the same speed. 
D) Both balls will reach the ground with the same kinetic energy. 
E) Both balls will take the same time to reach the ground. 
A) As they reach the ground,the 1-kg ball will have more kinetic energy than the 2-kg ball because it was dropped from a greater height. 
B) As they reach the ground,the 1-kg ball will be moving faster than the 2-kg ball. 
C) Both balls will reach the ground with the same speed. 
D) Both balls will reach the ground with the same kinetic energy. 
E) Both balls will take the same time to reach the ground.

Question 4

A tennis ball bounces on the floor three times,and each time it loses 23.0% of its energy due to heating.How high does it bounce after the third time,if we released it  
From the floor?

Accepted Answer

A) 180 cm 
B) 18 cm 
C) 180 mm 
D) 240 cm 
A) 180 cm 
B) 18 cm 
C) 180 mm 
D) 240 cm

Question 5

A rock falls from a vertical cliff that is 4.0 m tall and experiences no significant air resistance as it falls.At what speed will its gravitational potential energy (relative to the base of the cliff)be equal to its kinetic energy?

Accepted Answer

A) 3.1 m/s 
B) 4.4 m/s 
C) 6.3 m/s 
D) 8.9 m/s 
E) 13 m/s 
A) 3.1 m/s 
B) 4.4 m/s 
C) 6.3 m/s 
D) 8.9 m/s 
E) 13 m/s

Question 6

A 1500-kg car accelerates from rest to 25 m/s in 7.0 s.What is the average power delivered by the engine? (1 hp = 746 W)

Accepted Answer

A) 60 hp 
B) 70 hp 
C) 80 hp 
D) 90 hp 
A) 60 hp 
B) 70 hp 
C) 80 hp 
D) 90 hp

Question 7

Swimmers at a water park have a choice of two frictionless water slides,as shown in the figure.Although both slides drop over the same height h,slide 1 is straight while slide 2 is curved,dropping quickly at first and then leveling out.How does the speed v1 of a swimmer reaching the bottom of slide 1 compare with v2,the speed of a swimmer reaching the end of slide 2?

Accepted Answer

A) v1 > v2 
B) v1 2 
C) v1 = v2 
D) The heavier swimmer will have a greater speed than the lighter swimmer,no matter which slide he uses. 
E) No simple relationship exists between v1 and v2. 
A) v1 > v2 
B) v1 2 
C) v1 = v2 
D) The heavier swimmer will have a greater speed than the lighter swimmer,no matter which slide he uses. 
E) No simple relationship exists between v1 and v2.

Question 8

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

Question 9

How much work is required to stretch an ideal spring of spring constant (force constant)40 N/m from x = 0.20 m to x = 0.25 m if the unstretched position is at x = 0.00 m?

Accepted Answer

A) 0.45 J 
B) 0.80 J 
C) 1.3 J 
D) 0.050 J 
A) 0.45 J 
B) 0.80 J 
C) 1.3 J 
D) 0.050 J

Question 10

A bead is moving with a speed of 20 m/s at position A on the track shown in the figure.This track is friction-free,and there is no appreciable air resistance.What is the speed of the bead at point C?

Accepted Answer

A) 0 m/s 
B) 34 m/s 
C) 69 m/s 
D) 20 m/s 
E) We cannot solve this problem without knowing the mass of the bead. 
A) 0 m/s 
B) 34 m/s 
C) 69 m/s 
D) 20 m/s 
E) We cannot solve this problem without knowing the mass of the bead.

Question 11

Assuming negligible friction,what spring constant (force constant)would be needed by the spring in a "B-B gun" to fire a 10-g pellet to a height of 100 m if the spring is initially compressed by 0.10 m?

Accepted Answer

A) 20 N/cm 
B) 200 N/m 
C) 2000 N/cm 
D) 0.0020 N/m 
A) 20 N/cm 
B) 200 N/m 
C) 2000 N/cm 
D) 0.0020 N/m

Question 12

What is the net power needed to change the speed of a 1600-kg sport utility vehicle from 15.0 m/s to 40.0 m/s in 4.00 seconds?

Accepted Answer

A) 100 kW 
B) 10.0 kW 
C) 140 kW 
D) 14.0 kW 
E) 275 kW 
A) 100 kW 
B) 10.0 kW 
C) 140 kW 
D) 14.0 kW 
E) 275 kW

Question 13

If the units of your answer are kg ∙ m2/s3,which of the following types of quantities could your answer be? (There could be more than one correct choice. )

Accepted Answer

A) kinetic energy 
B) potential energy 
C) force 
D) power 
E) work 
A) kinetic energy 
B) potential energy 
C) force 
D) power 
E) work

Question 14

A girl throws a stone from a bridge.Consider the following ways she might throw the stone.The speed of the stone as it leaves her hand is the same in each case.
Case A: Thrown straight up.
Case B: Thrown straight down.
Case C: Thrown out at an angle of 45° above horizontal.
Case D: Thrown straight out horizontally.
In which case will the speed of the stone be greatest when it hits the water below if there is no significant air resistance?

Accepted Answer

A) Case A 
B) Case B 
C) Case C 
D) Case D 
E) The speed will be the same in all cases. 
A) Case A 
B) Case B 
C) Case C 
D) Case D 
E) The speed will be the same in all cases.

Question 15

A block slides down a frictionless inclined ramp and experiences no significant air resistance.If the ramp angle is 17.0° above the horizontal and the length of the surface of the ramp is  
Find the speed of the block as it reaches the bottom of the ramp,assuming it started sliding from rest at the top.

Accepted Answer

A) 10.7 m/s 
B) 114 m/s 
C) 7.57 m/s 
D) 19.6 m/s 
A) 10.7 m/s 
B) 114 m/s 
C) 7.57 m/s 
D) 19.6 m/s

Question 16

A stone is released from rest at a height h at the left side of a loop-the-loop,as shown in the figure.There is no appreciable friction from the track or from air resistance.If the radius of the loop is R,what is the minimum height h for which the stone will not fall off the track at the top of the loop?

Accepted Answer

A) 3.5 R 
B) 2.5 R 
C) 2.0 R 
D)    R 
E) 3.0 R 
A) 3.5 R 
B) 2.5 R 
C) 2.0 R 
D)    R 
E) 3.0 R

Question 17

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

Question 18

A prankster drops a water balloon from the top of a building.If the balloon is traveling at 29.1 m/s when it strikes a window ledge that is 1.5 m above the ground,how tall is the building? Neglect air resistance.

Accepted Answer

A) 45 m 
B) 43 m 
C) 46 m 
D) 47 m 
A) 45 m 
B) 43 m 
C) 46 m 
D) 47 m

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

Question 20

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

Exam 8: Potential Energy and Conservation of 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?

A 1-kg ball is released from a height of 6 m,and a 2-kg ball is released from a height of 3 m.Air resistance is negligible as they fall.Which of the following statements about these balls are correct? (There could be more than one correct choice. )

A tennis ball bounces on the floor three times,and each time it loses 23.0% of its energy due to heating.How high does it bounce after the third time,if we released it From the floor?

A rock falls from a vertical cliff that is 4.0 m tall and experiences no significant air resistance as it falls.At what speed will its gravitational potential energy (relative to the base of the cliff)be equal to its kinetic energy?

A 1500-kg car accelerates from rest to 25 m/s in 7.0 s.What is the average power delivered by the engine? (1 hp = 746 W)

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.

How much work is required to stretch an ideal spring of spring constant (force constant)40 N/m from x = 0.20 m to x = 0.25 m if the unstretched position is at x = 0.00 m?

A bead is moving with a speed of 20 m/s at position A on the track shown in the figure.This track is friction-free,and there is no appreciable air resistance.What is the speed of the bead at point C?

Assuming negligible friction,what spring constant (force constant)would be needed by the spring in a "B-B gun" to fire a 10-g pellet to a height of 100 m if the spring is initially compressed by 0.10 m?

What is the net power needed to change the speed of a 1600-kg sport utility vehicle from 15.0 m/s to 40.0 m/s in 4.00 seconds?

If the units of your answer are kg ∙ m2/s3,which of the following types of quantities could your answer be? (There could be more than one correct choice. )

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 prankster drops a water balloon from the top of a building.If the balloon is traveling at 29.1 m/s when it strikes a window ledge that is 1.5 m above the ground,how tall is the building? Neglect air resistance.

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?

Introduction to Physics

One-Dimensional Kinematics

Vectors in Physics

Two-Dimensional Kinematics

Newtons Laws of Motion

Applications of Newtons Laws

Work and Kinetic 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

Filters

If the units of your answer are kg ∙ m²/s³,which of the following types of quantities could your answer be? (There could be more than one correct choice. )