n 80-kgkg quarterback jumps straight up in the air right before throwing a 0.43-kgkg football horizontally at 15 m/sm/s. How fast will he be moving backward just after releasing the ball

0.080625 m/s

Explanation:

According the Newton's second law of motion, which specifies conservation of Momentum.

(Momentum of the ball moving away) + (momentum of the quarterback) = 0

0.43 * 15 = - (80 * v)

v = - (0.43 * 15) / 80

v = - 0.080625 m/s

The minus indicates that the quarter back moves backwards.

Given:

Mass, Mq = 80 kg

Mass, Mf = 0.43 kg

velocity, Vf = 15 m/s

Using the momentum - conservation theory,

Mq * Vq = Mf * Vf

80 * Vq = 0.43 * 15

V = 0.0806

= 0.081 m/s