A 12 g bullet is fired into a 9.0 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.
What was the speed of the bullet?
(please help, I've tried setting this problem up multiple times and can't get it right)

Question

A 12 g bullet is fired into a 9.0 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. 
What was the speed of the bullet?
(please help, I've tried setting this problem up multiple times and can't get it right)

ajprincess · Answer

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Using $ v^2=u^2+2as$
${v_4}^2={v_3}^2-2as$
Here
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Then using conservation of momentum principle
$mv+m_1v_1=(m+m_1)v_3$
$0.012v=9.012*2as$
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