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?

- 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

:-)