"Sort the following objects as part of the system or not."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?

0.080625 m/s

Explanation:

Horizontally, the total momentum must be conserved, meaning the momentum before and after the throw must be the same.

The total momentum before the throw is 0, and so is after the throw:

mv + MV = 0

where m, M are the masses of the ball and the quarterback, respectively. v and V are the velocities of the ball and the quarterback, respectively.

0.43*15 + 80V = 0

80V = -6.45

V = -6.45 / 80 = -0.080625 m/s

So he will be moving in the opposite direction with the ball at the rate of 0.080625 m/s