To practice Problem-Solving Strategy 11.1 for conservation of momentum problems. An 80-kg quarterback jumps straight up in the air right before throwing a 0.43-kg football horizontally at 15 m/s. How fast will he be moving backward just after releasing the ball?

Question

Physics

Nick Norris

23 July, 20:29

To practice Problem-Solving Strategy 11.1 for conservation of momentum problems. An 80-kg quarterback jumps straight up in the air right before throwing a 0.43-kg football horizontally at 15 m/s. How fast will he be moving backward just after releasing the ball?

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Answers (1)

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Matthias Kelley · Answer 1

0.081 m / s

Explanation:

According to the conservation of momentum, the momentum of a system is conserved when no external force is applied on a body.

momentum of the system before throwing = momentum of the system after throwing

Let v be the velocity of quarterback after throwing the football.

80 x 0 + 0.43 x 0 = 80 x v + 0.43 x 15

0 = 80 v + 6.45

v = - 0.081 m / s

The negative sign shows that he is moving in backward direction.