# Physics Conservation of Energy

posted by
**Casey**
.

A car traveling at 20 miles/hour stops in a distance of 15 feet when its brakes are locked. Assuming that the frictional force doesn't depend on speed, that same car traveling at 60 miles/hour will stop in a distance closest to

a. 15 feet

b. 45 feet

c. 90 feet

d. 135 feet

My answer: c