Question

A 0.0010 kg pellet is fired at a speed of 50.0 m/s at a motionless 0.35 kg piece of balsa wood . when the pellet hits the wood, it sticks in the wood and they slide off together. With what speed do they slide?

Answer 1

- Law of conservation of momentum!
let p = momentum
u = initial velocity
v = final velocity

∑p(initial) = ∑p(final)
m1u1 + m2u2 = (m1 + m2)(v2)
(0.001)(50) + (0.35)(0) = (0.35 + 0.001)(v2)
v2 = (0.001)(50) / (0.35 + 0.001)
v2 = 0.142 ms^-1 in initial direction
:-)