A popular swinging-balls apparatus consists of an aligned row of identical elastic balls that are suspended by strings so they barely touch each other. When two balls are lifted from one end and released, they strike the row and two balls pop out from the other end. If instead one ball popped out with twice the speed of the two, this would be a violation of conservation of:

a. momentum
b. kinetic energy
c. both of these
d. none of these

b. kinetic energy

Explanation:

A popular swinging-balls apparatus consists of an aligned row of identical elastic balls that are suspended by strings so they barely touch each other. When two balls are lifted from one end and released, they strike the row and two balls pop out from the other end. If instead one ball popped out with twice the speed of the two, this would be a violation of conservation of kinetic energy.

Kinetic energy is the is energy of an object in motion; in swinging the balls,K.E would not be conserved in the collision though the momentum would be conserved in such release.

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