Elasticno kinetic energy losttotal momentum 6.00 kg·m/s before and after
positive direction2.0 kg3.0 m/s1.0 m/s1.0 kg4.0 m/s

Momentum, kg·m/s

cart 1 before
6.00
cart 2 before
0.00
total before
6.00
cart 1 after
2.00
cart 2 after
4.00
total after
6.00

Kinetic energy, J

cart 1 before
9.00
cart 2 before
0.00
total before
9.00
cart 1 after
1.00
cart 2 after
8.00
total after
9.00

e = 1 is elastic, e = 0 is perfectly inelastic (the carts stick together). Anything between is an ordinary inelastic collision.

QuantityBeforeAfter
Cart 1 velocity3.00 m/s1.00 m/s
Cart 2 velocity0.00 m/s4.00 m/s
Total momentum6.00 kg·m/s6.00 kg·m/s
Total kinetic energy9.00 J9.00 J
Kinetic energy lostn/a0.00 J

Drag anything and watch the two momentum bars trade size while the total bar holds still. That is conservation of momentum, and it holds at every value of e. The kinetic energy total only holds still at e = 1.

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