Answer:
1. The mass of the quarterback = known = 80 kg
2. The mass of the football = known = 0.43 kg
3. The horizontal velocity of quarterback before throwing the ball = known = 0
4. The horizontal velocity of football before being thrown = known = 0
5. The horizontal velocity of quarterback after throwing the ball, = unknown quantity and it can be calculated using the conservation of linear momentum.
6. The horizontal velocity of football after being thrown = known = 15 m/s
Explanation:
Given that,
Mass of the quarterback, m = 80 kg
Mass of the football, m' = 0.43 kg
Speed of the football, v' = 15 m/s
We need to sort the following quantities as known or unknown.
1. The mass of the quarterback = known = 80 kg
2. The mass of the football = known = 0.43 kg
3. The horizontal velocity of quarterback before throwing the ball = known = 0
4. The horizontal velocity of football before being thrown = known = 0
5. The horizontal velocity of quarterback after throwing the ball, = unknown quantity and it can be calculated using the conservation of linear momentum.
6. The horizontal velocity of football after being thrown = known = 15 m/s
