Answer:
6.13428 rev/s
Explanation:
= Final moment of inertia = 4.2 kgm²
I = Moment of inertia with fists close to chest = 5.7 kgm²
= Initial angular speed = 3 rev/s
= Final angular speed
r = Radius = 76 cm
m = Mass = 2.5 kg
Moment of inertia of the skater is given by

In this system the angular momentum is conserved

The rotational speed will be 6.13428 rev/s
Answer:
0.0241875 m
Explanation:
= Mass of quarterback = 80 kg
= Mass of football = 0.43 kg
= Velocity of quarterback
= Velocity of football = 15 m/s
Time taken = 0.3 seconds
In this system as the linear momentum is conserved

Assuming this velocity is constant

The distance the quarterback will move in the horizontal direction is 0.0241875 m