Energy Conservation - 5 Steps to a 5 500 AP Physics Questions to Know by Test Day

5 Steps to a 5 500 AP Physics Questions to Know by Test Day (2012)

Chapter 6. Energy Conservation

151. A 70-kg man runs at a constant velocity of 2 m/s. What is his kinetic energy?

(A) 35 J

(B) 70 J

(C) 105 J

(D) 140 J

(E) 210 J

152. A 10-N force is applied horizontally on a box to move it 10 m across a frictionless surface. How much work was done to move the box?

(A) 0 J

(B) 10 J

(C) 50 J

(D) 100 J

(E) 1,000 J

153. A constant net force of 500 N moves a 1,000-kg car 100 m. If the car was initially at rest, then what is the car’s final velocity?

(A) 1 m/s

(B) 5 m/s

(C) 10 m/s

(D) 20 m/s

(E) 100 m/s

154. A mover uses a pulley system to lift a grand piano with a mass of 500 kg from the ground to a height of 10 m. What is the change in the piano’s gravitational potential energy?

(A) 5 × 102 J

(B) 5 × 103 J

(C) 5 × 104 J

(D) 5 × 105 J

(E) 5 × 106 J

155. A boy pulls a 10-kg box across an ice rink across a distance of 50 m. He exerts a constant force of 10 N on a rope attached to the box at an angle of 60°. How much work has he done on the box?

(A) 50 J

(B) 100 J

(C) 200 J

(D) 250 J

(E) 500 J

156. A 5-kg ball rolls down a hill from a height of 10 m. The ball starts from rest. What is the ball’s velocity at the bottom of the hill?

(A) 5 m/s

(B) 10 m/s

(C) 14 m/s

(D) 24 m/s

(E) 30 m/s

157. An archer pulls a bowstring back a distance of 1.5 m with 450 N of force. The arrow has a mass of 20 g. When he releases the string, what is the velocity of the arrow when it leaves the bow?

(A) 100 m/s

(B) 200 m/s

(C) 260 m/s

(D) 360 m/s

(E) 500 m/s

158. A car traveling at 30 m/s must stop within 10 m to avoid a crash. What magnitude of force must the brakes exert on the car?

(A) 1.5 × 103 N

(B) 3.0 × 103 N

(C) 4.5 × 103 N

(D) 1.5 × 104 N

(E) 4.5 × 104 N

159. A bullet has a mass of 7.5 g. It is fired into a ballistic pendulum. The pendulum’s receiving block of wood is 2.5 kg. After the collision, the pendulum swings to a height of 0.1 m. What is the approximate velocity of the bullet?

(A) 50 m/s

(B) 100 m/s

(C) 200 m/s

(D) 250 m/s

(E) 500 m/s

160. [For Physics C Students Only] An object is placed in an elastic device and displaced from the equilibrium point. The force as a function of displacement is shown in this graph. When the object is displaced by 2 m, what is the total potential energy that it has?

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(A) 20 J

(B) 25 J

(C) 30 J

(D) 50 J

(E) 60 J

161. A spring with a constant of 300 N/m is stretched by 0.5 m. What is the force on the spring?

(A) 50 N

(B) 100 N

(C) 150 N

(D) 200 N

(E) 300 N

162. A spring with a constant of 400 N/m is stretched by 0.5 m. What is the potential energy on the spring?

(A) 50 J

(B) 100 J

(C) 150 J

(D) 200 J

(E) 300 J

163. A 1-kg block is attached to a spring with a constant of 100 N/m. The spring is compressed 0.2 m from equilibrium. When the block is let go, what is its velocity as it passes the equilibrium point?

(A) 0.4 m/s

(B) 1.4 m/s

(C) 1.6 m/s

(D) 2.0 m/s

(E) 4.0 m/s

164. Two cannons fire identical cannon balls with the same amount of powder. The barrel of Cannon 2 is twice as long as the barrel of Cannon 1. How does the velocity of a cannon ball fired from Cannon 2 compare with the ball fired from Cannon 1?

(A) Four times that of Cannon 1

(B) Twice that of Cannon 1

(C) 1.4 times that of Cannon 1

(D) One-half that of Cannon 1

(E) The same as Cannon 1

165. A 750-kg aircraft is flying level at 100 m/s. A tailwind blows constantly for 1,200 m and the aircraft’s speed increases to 120 m/s. What is the force of the tailwind?

(A) 125 N

(B) 250 N

(C) 2,500 N

(D) 5,000 N

(E) 7,500 N

166. [For Physics C Students Only] This graph depicts the potential energy of an object that varies with the distance, x. Which of the following statements describes the force on the object?

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(A) The force is constant.

(B) The force changes, but it is always negative.

(C) The force changes, but it is always positive.

(D) The force changes linearly with a positive slope.

(E) The force changes linearly with a negative slope.

167. A force of 2.0 N exerted on an object for 5.0 m increased the object’s velocity by 1.0 m/s. What was the mass of the object?

(A) 0.1 kg

(B) 0.2 kg

(C) 1.0 kg

(D) 20 kg

(E) 200 kg

168. A 70-kg stuntman free falls from a building for 125 m and hits an airbag. The airbag exerts a force on him as he depresses it 5.0 m and comes to a complete stop. What is the force exerted by the air bag?

(A) 1.00 × 102 N

(B) 2.75 × 102 N

(C) 1.75 × 103 N

(D) 2.75 × 103 N

(E) 1.00 × 104 N

169. A man pushes a 100-kg box with a horizontal force of 100 N across a floor for a distance of 60 m in 2 min. What is his power?

(A) 10 W

(B) 20 W

(C) 30 W

(D) 40 W

(E) 50 W

Questions 170–172 are based on the following figure:

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170. The diagram above depicts a roller coaster track with various locations labeled A through E. At which locations will a roller coaster car have the same potential energy?

(A) A and E

(B) B and C

(C) C and D

(D) B and E

(E) A and C

171. In this diagram, at which location will the roller coaster car move the fastest?

(A) A

(B) B

(C) C

(D) D

(E) E

172. For this diagram, at which point will the total energy be the greatest?

(A) A

(B) B

(C) D

(D) E

(E) The total energy is the same at all points

173. A man pushes a lawnmower with a handle at an angle of 60°. He applies a constant 20 N force and moves the lawnmower a horizontal distance of 100 m in 5 min. What is the power of his efforts?

(A) 3 W

(B) 7 W

(C) 10 W

(D) 17 W

(E) 27 W

174. A 2,000-kg airplane flies at 343 m/s. What is its kinetic energy?

(A) 1.18 × 104 J

(B) 1.18 × 105 J

(C) 3.43 × 105 J

(D) 1.18 × 108 J

(E) 3.43 × 108 J

175. A marksman fires a 7.5-g bullet from a 1.2-kg handgun. The bullet travels away at 365 m/s. The bullet strikes a target and loses all its energy as heat (500 J). If the length of the gun barrel is 125 mm, then how much force did the handgun exert on the bullet?

(A) 500 N

(B) 1,000 N

(C) 2,000 N

(D) 4,000 N

(E) 5,000 N

176. Two air cars weighing 500 g each are on a frictionless track. Car A is moving at 0.2 m/s when it collides into Car B, which is at rest. Both cars move away at 0.1 m/s. How much energy is lost as heat during the collision?

(A) 10 percent

(B) 20 percent

(C) 25 percent

(D) 50 percent

(E) 90 percent

177. A rifle fires a 4.0-g bullet at a velocity of 950 m/s. If the length of the rifle barrel is 1.01 m, then what force does the rifle exert on the bullet?

(A) 180 N

(B) 580 N

(C) 1,800 N

(D) 5,800 N

(E) 18,000 N

178. A 2,700-kg cannon fires an 11-kg cannon ball. The length of the cannon’s barrel is 244 m. If the powder produces 2.25 × 104 N of force, what is the velocity of the cannonball?

(A) 10 m/s

(B) 50 m/s

(C) 100 m/s

(D) 200 m/s

(E) 500 m/s

179. A 5-kg rubber bowling ball rolls down a 10-m frictionless ramp inclined at 45° as seen in the figure. It rolls out onto a concrete floor. The coefficient of friction between the rubber and concrete is 0.6.

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(a) What is the velocity of the ball when it reaches the bottom of the ramp?

(b) What is the kinetic energy of the ball at the bottom of the ramp?

(c) How far does the ball travel before coming to a complete stop?

(d) How long does it take for the ball to roll from the bottom of the ramp until it comes to a complete stop?

180. A tall sailing ship (m = 1.43 × 106 kg) is moving along the ocean as depicted in the figure at an initial velocity of 10 km/h. A wind blows constantly at a 60° angle as shown. The wind blows on the ship over a distance of 1 km. The ship’s final velocity is 13 km/h.

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(a) What is the change in velocity of the ship in m/s?

(b) What is the ship’s change in kinetic energy?

(c) What is the force of the wind?