Question

A 29 g rubber bullet is travelling to the right at 200 m/s, when it hits a 1.1 kg block of wood sitting on a horizontal frictionless surface. If this collision is inelastic (though not perfectly inelastic), and the velocity of the block of wood after the collision is 6.85 m/s to the right, what is the velocity of the bullet after the collision? Give your answer in m/s and treat right as the positive direction and left as the negative direction. (Include the sign in your answer if it is a negative value, and no sign if the answer is positive.)

Answer 1

Show your work for further assistance; don't just dump your assignments here.

Answer 2

i'm just unsure of what formula i should apply!

Answer 3

so i found a formula: m1v1ix +m2v2ix = m1v1fx + m2v2fx
which i rearranged to find v1fx and eliminated m2v2ix because m2v2ix = 0
so the eqn looked like: v1fx = (m1v1ix - m2v2fx)/m1
subbing in i got: [(0.029)(200) - (1.1)(6.25)]/(0.029)
which gave the answer -59.8276. is this correct?

Answer 4

You are using the right equation, but the 6.25 does not agree with the original 6.85 for v2fx