1. Couid not get b and d for the following problem: A football player of mass 99
ID: 1534419 • Letter: 1
Question
1. Couid not get b and d for the following problem: A football player of mass 99 kg is running at a speed of 7.9 m/s when he catches a ball thrown by the quarterback. The mass of the ball is 0.41 kg it has a speed of 24 m/s just before the player caught it.
a) Assuming that the player catches the ball with his feet off the ground and both the player and ball are moving horizontally and in the same direction, calculate the final velocity of the ball and player. ( I got this answer correct and to b 7.97 m/s)
b) Calculate the loss of kinetic energy in this case.
c) Instead the ball is was intercepted by the safety of the same mass but running in the opp direction at the same speed of 7.9 m/s. what's the final speed in this situation? ( Got correct and 7.77 m/s was my answer)
d) What's the loss in kinetic energy for the second case?
Explanation / Answer
b)
loss in kinetic energy
delta K = initial - final kinetic energy
initial KE = 0.5 m1 (7.9^2) + 0.5 m2 (24^2)
similarily
final KE = 0.5 (m1+m2) Vf^2
we get
loss in kinetic energy = 52.91 J
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