BEST PRACTICE Conservation of Energy

Question 1 of 3: A pendulum swings to a maximum height of 2.5 meters as shown. The mass of the ball is 4.0 kg. Air resistance is negligible. What is the potential energy of the ball at the maximum height?

• 100 J

• 10 J

• 40 J

• 25 J

Question 2 of 3: A pendulum swings to a maximum height of 2.5 meters as shown. The mass of the ball is 4.0 kg. Air resistance is negligible. What is the kinetic energy of the ball at the lowest point?

• 100 J

• 10 J

• 40 J

• 25 J

Question 3 of 3: A pendulum swings to a maximum height of 2.5 meters as shown. The mass of the ball is 4.0 kg. Air resistance is negligible. What is the speed of the ball at the lowest position?

• 6.3 m/s

• 7.1 m/s

• 25 m/s

• 50 m/s

Question 1 of 2: The figure shows a ball on a curved track. The ball of mass 2 kg starts from rest at the top of the track. It then rolls from the top of the track to the horizontal part at the ground. If friction is ignored, its speed just at the moment it reaches the ground is expected to be 14 m/s. What is the height, h, from the ground to the top of the track?

• 0.7 m

• 4.9 m

• 9.8 m

• 19.6 m

Question 2 of 2: The figure shows a ball on a curved track. The ball of mass 2 kg starts from rest at the top of the track. It then rolls from the top of the track to the horizontal part at the ground. If friction is ignored, its speed just at the moment it reaches the ground is expected to be 14 m/s. The speed of the ball at the bottom of the track was actually 10 m/s. How much energy was lost as the ball moves down the track?

• 186 J

• 4 J

• 20 J

• 96 J

Question 1 of 3: In an experiment, a basketball of mass 0.63 kg was dropped at a height of 1.5 meters. It bounces off the floor and reached a maximum height of 0.90 m. What is the speed of the basketball as it hits the ground?

• 30 m/s

• 5.5 m/s

• 18 m/s

• 4.2 m/s

Question 2 of 3: In an experiment, a basketball of mass 0.63 kg was dropped at a height of 1.5 meters. It bounces off the floor and reached a maximum height of 0.90 m. What is the speed of the basketball as it bounces off the ground?

• 30 m/s

• 5.5 m/s

• 18 m/s

• 4.2 m/s

Question 3 of 3: In an experiment, a basketball of mass 0.63 kg was dropped at a height of 1.5 meters. It bounces off the floor and reached a maximum height of 0.90 m. The energy lost as the ball bounces off the ground is nearly

• 6 J

• 9 J

• 13 J

• 4 J

Question 1 of 2: A 10.0-kg test rocket is fired vertically from the ground. When it reached a height of 20.0 m, it burns out of fuel. Its fuel gave it a kinetic energy of 1960 J by the time the rocket engine burns all of the fuel. What additional height will the rocket rise?

• 20.0 m

• 19.6 m

• 196 m

• 4.43 m

Question 2 of 2: A 10.0-kg test rocket is fired vertically from the ground. When it reached a height of 20.0 m, it burns out of fuel. Its fuel gave it a kinetic energy of 1960 J by the time the rocket engine burns all of the fuel. What will the rocket’s speed be just before it hits the ground?

• 800 m/s

• 400 m/s

• 28 m/s

• 20 m/s