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Question
Answer carefully, with reason:
In an elastic collision of two billiard balls, is the total kinetic energy conserved during the short time of collision of the balls (i.e. when they are in contact)?
Solution
During a collision, when balls are in contact, the kinetic energy of the balls is transformed into potential energy. The kinetic energy remains the same before and after the collision. Therefore, in the described elastic collision, the total kinetic energy is not conserved.
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