A racing dog is initially running at 15.0 m/s, but is slowing down.How fast is the dog moving when its kinetic energy has been reduced by half? By what fraction has its kinetic energy been reduced when its speed has been reduced by half?

Answer 1

A car travels at a constant speed around a circular track whose radius is 2.8 km. The car goes once around the track in 300 s. What is the magnitude of the centripetal acceleration of the car?

Answer 2

Reducing V by a factor 1/sqrt2 = 0.70711 reduces kinetic energy by half.

If you reduce speed by half, KE decreases to 1/4 the former value.

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