Physics Question?

Question

Olaf is standing on a sheet of ice that covers the football stadium parking lot in Buffalo, New York; there is negligible friction between his feet and the ice. A friend throws Olaf a ball of mass 0.400 kg that is traveling horizontally at 11.7 m/s. Olaf's mass is 68.4 kg.

1. If Olaf catches the ball, with what speed "v" do Olaf and the ball move afterward? Express your answer numerically in centimeters per second.

2. If the ball hits Olaf and bounces off his chest horizontally at 8.00 m/s in the opposite direction, what is his speed "v" after the collision? Express your answer numerically in centimeters per second.

Answer 1

The problem is a momentum conservation problem.
1. 0.4 * 11.7 = (68.4 + 0.4) * v
v = 6.8 cm/s

2. 0.4 * 11.7 = (68.4 * v) - (0.4 * 8)
v = 11.5 cm/s

Answer 2

(1)
.400 x 11.7 + 68.4 x 0 = (.400 + 68.4) x Vfinal
4.68 = 68.8 x Vfinal
Vfinal = .068 m/s = 6.8 cm/s

(2)
4.68 = .400 x 8.00 + 68.4 x Vfinal
4.68 = 3.2 + 68.4 x Vfinal
1.48 = 68.4 x Vfinal
Vfinal = .022 m/s = 2.2 cm/s

these answers are correct.. in the 2nd answer, the total momentum must add up to 4.68 after the collision (assuming no losses of energy), the same as before the collision,
so 4.68 = final momentum of ball + final momentum of Olaf.. we do not use negative(-) based on the final direction of the ball in this case.

Answer 3

You have to find the momentum before and after. They should be equal to one another if there is no loss.

Both problems are the same.

Answer 4

AP Physics is tough. If your math grades are at least a B then I would consider taking AP Physics. It will be tough for you unless you are really strong in math.

Answer 5

Both are conservation of momentum problems

Answer 6

conservation of momentum