Energy Unit Review

Batman and Robin are having a lifting competition. Batman claims that he has a greater power output than Robin. Batman can lift a sack 2.0 m vertically with a 98 N net force in 3 seconds. Robin counters and says he can lift the same sack 5.0 m vertically with a 196 N net force in 20 seconds.

1. Draw an LOL Diagram for each bag when
   1. The bag is motionless on the ground
   2. The bag has been lifted to its new vertical height

1. Who has a greater power output? Use your energy models to show all your work.

Given(s)	Unknown(s)	Equation(s)	Substitution(s)	Solution

A 0.15 kg baseball traveling at 30 m/s moves a catcher's glove backward by 0.35 m when the ball is caught.

1. Draw an LOL diagram for the glove when
   1. The glove is held motionless 0.75 m above the ground, waiting for the ball
   2. The glove is been moved backward by the baseball

1. How much Kinetic Energy does the baseball have? How much work does the ball do on the glove?

Given(s)	Unknown(s)	Equation(s)	Substitution(s)	Solution

1. What was the force exerted on the glove by the ball?

Given(s)	Unknown(s)	Equation(s)	Substitution(s)	Solution

A potato with a mass of 0.01 kg is fired from a launcher that has a 0.80 m long barrel.

1. How much work is done on the potato if the net force exerted on the potato by the launcher is 5000 N? What is the kinetic energy of the potato after it is launched?

Given(s)	Unknown(s)	Equation(s)	Substitution(s)	Solution

1. What speed would the potato reach?

Given(s)	Unknown(s)	Equation(s)	Substitution(s)	Solution

1. If the launcher acted on the potato for 0.2 seconds, how much power does the launcher use?

Given(s)	Unknown(s)	Equation(s)	Substitution(s)	Solution