Final answer:
The original momentum of the fullback is 319.8 kg·m/s to the east. The impulse on both the fullback and the tackler is 319.8 kg·m/s, but it's negative for the fullback (to the west) and positive for the tackler (to the east). The average force exerted on the tackler is approximately -376.2 N to the west.
Step-by-step explanation:
The original momentum of the fullback who is running to the east can be calculated using the formula momentum (p) = mass (m) × velocity (v). Therefore, the initial momentum is p = 82 kg × 3.9 m/s, which equals 319.8 kg·m/s to the east (positive value).
The impulse exerted on the fullback can be found by calculating the change in momentum, which is the final momentum minus the initial momentum. Since the fullback is stopped, the final velocity and hence the final momentum is 0. Therefore, the impulse is equal to -319.8 kg·m/s (since it brings the player to a stop, the impulse is negative indicating it's in the opposite direction, to the west).
The impulse exerted on the tackler is equal in magnitude and opposite in direction to the impulse exerted on the fullback due to Newton's third law, which states that for every action, there is an equal and opposite reaction. Hence, the impulse on the tackler is also 319.8 kg·m/s but in the negative direction (to the west).
The average force exerted on the tackler can be calculated using the impulse formula, impulse = average force (F) × time (t). Rearranging for force, we get F = impulse / t. Thus, the average force exerted on the tackler is F = -319.8 kg·m/s / 0.85 s, resulting in an average force of approximately -376.2 N (to the west).