Posted by **John** on Monday, October 12, 2009 at 11:41pm.

A 2.0 kg mass is moving to the right at 3.0 m/s . A 4.0 kg mass is moving to the left at 2.0 m/s.

A) If after the collision the two masses join together what is their velocity after the collision?

3.0 X 2.0 = 6m/s. Is this correct?

B)Is this a elastic or inelastic collision?

Elastic. Is this correct?

- Physics -
**MathMate**, Tuesday, October 13, 2009 at 8:21am
3.0 X 2.0 = 6m/s. Is this correct?

The unit is not correct: 3 kg * 2 m/s gives 6 kg-m/s.

This is not the answer, but the momentum of the left mass.

Calculate the momentum of the right mass and add to that of the left (watch the sign) to get the total momentum.

Divide the total momentum by the total mass to get the velocity after the inelastic impact.

An elastic impact is like bouncing a superball on the wall, and an inelastic impact is like dropping mashed potatoes on the floor. Hope you get the idea.

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