Question
Jay rides his 2.0-kg skateboard. He is moving at speed 5.8 m/s when he pushes off the board and continues to move forward in the air at 5.4 m/s. The board now goes forward at 13 m/s.
A. Determine Jay’s mass.
B. Determine the change in the internal energy of the system during this process.
(Express your answer to two significant figures and include the appropriate units.)
A. Determine Jay’s mass.
B. Determine the change in the internal energy of the system during this process.
(Express your answer to two significant figures and include the appropriate units.)
Answers
oobleck
A. conserve momentum. If Jay's mass is m, then
5.8(m+2) = 13*2 +5.4m
m = 36 kg
B. Now just figure the KE for Jay and the board: KE = 1/2 mv^2
Initially, KE = 1/2 * (36+2) * 5.8 = 110.2J
Now find the final KE and compare
5.8(m+2) = 13*2 +5.4m
m = 36 kg
B. Now just figure the KE for Jay and the board: KE = 1/2 mv^2
Initially, KE = 1/2 * (36+2) * 5.8 = 110.2J
Now find the final KE and compare