Answer to Question #256543 in Physics for Morgan Hopkin

Question

Object A has a mass of 4.8 kg and is moving at 4.5 m/s when it collides head-on with a stationary object B of mass of 6.0 kg. Object A rebounds directly backward with a velocity of 0.30 m/s while object B moves forward with a velocity of 4.0 m/s. Determine whether the collision is elastic.

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Your Answer:

Answer 1

In absolutely elastic collision, the energy is conserved. Compare the initial and final energy:

$$KE_\text{initial}=\frac12mv_m^2=43.5375\text{ J},\\\space\\ KE_\text{final}=\frac12mu_m^2+\frac12Mu_M^2=48.216\text{ J}.\\\space\\ KE_\text{final}\neq KE_\text{initial}.$$

The collision is inelastic.