What was the speed of the bullet?

Question

A 10 g bullet is fired into a 10 kg wood block that is at rest on a wood table. The block, with the bullet embedded, slides 5.0 cm across the table. The coefficient of kinetic friction for wood sliding on wood is 0.20.

Answer 1

First, let's find the speed of the block with the bullet embedded inside

The work done by friction is equal to the starting KE
.5*10.01*v^2=10.01*9.81*0.20*0.50
v=0.44 m/s

Now, using conservation of momentum, find the speed of the bullet
.01*v=10.01*0.44
v=443 m/s

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