20.Two balls are in motion. A 2-kg ball moving at 4m/s and a 4-kg ball moving at 2m/s, which one has greater kinetic energy? a. 2 kg ball moving at 4 m/s c. Both balls have the same KE b. 4 kg ball moving at 2 m/s d. Cannot be determined

A

Explanation:

Given that two balls are in motion. A 2-kg ball moving at 4m/s and a 4-kg ball moving at 2m/s, which one has greater kinetic energy? a. 2 kg ball moving at 4 m/s c. Both balls have the same KE b. 4 kg ball moving at 2 m/s d. Cannot be determined

The formula for kinetic energy is :

K.E = 1/2mv^2

A 2-kg ball moving at 4m/s will have kinetic energy of 1/2 × 2 × 4^2

K.E = 16J

and a 4-kg ball moving at 2m/s will have kinetic energy of 1/2 × 4 × 2^2

K.E = 2 × 4

K.E = 8J

which one has greater kinetic energy? Definitely it is a 2 kg ball moving at 4 m/s. Since 16J is greater than 8J. The correct answer is A.

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