# Kinetic energy dissipated during inelastic collsion

**1. The problem statement, all variables and given/known data**

Blocks A and B are moving toward each other. Block A has a mass of 2.0 kg and a velocity of 50 m/s, while B has a mass of 4.0 kg and a velocity of -25 m/s. They suffer a completely inelastic collision. The kinetic energy dissipated during the collision is:

**2. Relevant equations**

**3. The attempt at a solution**

So my professor has already worked out this problem, but I’m having trouble understanding why she picked the equations she did and how she manipulated them.

m_{1}v_{1i}-m_{2}v_{2i}=(m_{1}+m_{2})V

Plug in the numbers and you get V=0

ΔK=[itex]\frac{1}{2}[/itex](m_{1}+m_{2})V^{2}-([itex]\frac{1}{2}[/itex]m_{1}v_{1i}^{2}+[itex]\frac{1}{2}[/itex]m_{2}v_{2i}^{2})

Plug in and get -3750J

http://ift.tt/PmdIMl

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