The kinetic energy, K, of an object varies jointly with its mass, m, and the square of its velocity, v. The mass of an object stays the same, but the velocity of the object is halved. How is the kinetic energy of the object affected?

Kinetic energy varies jointly with mass and the square of velocity, so K is proportional to m v². The mass stays the same, while halving the velocity changes v² by a factor of (1/2)² = 1/4. Therefore, the kinetic energy is quartered, matching “The kinetic energy is quartered.”

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