A 5.00-g bullet is fired into a 500-g block of wood suspended as a ballistic pendulum. the combined mass swings up to a height of 8.00 cm. What was the magnitude of the momentum of the combined mass immediately after the collision?

Question

A 5.00-g bullet is fired into a 500-g block of wood suspended as a ballistic pendulum. the combined mass swings up to a height of 8.00 cm. What was the magnitude of the momentum of the combined mass immediately after the collision?
Answer
a. 	0.394 kg·m/s
b. 	0.632 kg·m/s
c. 	6.25 ´ 10–3 kg·m/s
d. 	6.25 kg·m/s

Damon · Accepted Answer

total mass = .5 + .005 = .505 kg potential energy = m g h = .505*9.81*.08 = .396 Joules that is Ke at bottom (1/2) (.505) v^2 = .396 v = 1.25 m/s momentum = m v = .505 * 1.25 = .633 kg m/s