Posted by **Andrea** on Sunday, July 18, 2010 at 10:52pm.

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?

- physics -
**Anonymous**, Sunday, July 18, 2010 at 11:44pm
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?

- physics (Andrea's question) -
**drwls**, Monday, July 19, 2010 at 12:33am
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.

Anonymous: Please post your quesstions separately using "Post a New Question"

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