A object of mass "m" travelling with speed "v" has a head-on collision with another object of mass "m" travelling with speed "v" in the opposite direction, the object sticks together after the collision.What is the total loss of kinetic energy in the collision?
Correct answer: C. mv2
- A. 0
- B. 1/2mv2
- C. mv2
- D. 2mv2
Explanation
Since there are two equal masses travelling with the equal velocity. Therefore according to the law of conservation of kinetic energy;Kinetic energy of the system before collision is equal to the kinetic energy of the system after collision is zero because they stick together and comes at rest.So loss is,1/2mv2 + 1/2mv2=0 1⁄2(mv2+ mv2)=0 2/2mv2=0Mv2=0Therefore the loss in kinetic energy is mv2.
This question appeared on the ETEA MDCAT 2017 paper, which you can sit online with every answer explained.
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About Collisions
Collisions involve the conservation of linear momentum when bodies interact for a short time. The topic covers impulse, elastic and inelastic collisions, kinetic energy changes, and the coefficient of restitution, with calculations usually based on one dimensional motion. Momentum remains conserved in isolated collisions, but kinetic energy is conserved only in elastic collisions.
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