# Homework help!?

Use the equation provided to solve the following.

Blocks M and m are released from rest when m is a height h above the ground. What is the speed of block m just before it hits the ground. The coefficient of kinetic friction between M and the floor is µk.

### 1 Answer

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- NCSLv 72 months agoFavourite answer
Ki + Ui + Wext = Kf + Uf + ΔEth

0 + mgh + 0 = Kf + 0 + µk*Mgh

so

Kf = (m - µk*M)*gh

and also Kf = ½*(m+M)V²

V² = 2*(m - µk*M)*g*h / (m+M)

and for the speed, take the square root.

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