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.

Explanation:

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

if the thermos has a vacuum innner, then heat through conv currents and conduction are reduced = vacuum flask