A baseball weighting 5 ounces and flying at 96 miles per hou

A baseball weighting 5 ounces and flying at 96 miles per hour hits the fence. What is the magnitude of kinetic energy in Btu which will be lost from baseball as it comes to a full stop?

Solution

converting into SI unit

Weight m = .141 kg

speed in m/sec = 42.92 m/s.

So kinetic energy = 1/2 m v^2 = 1/2*.141* 42.92*42.92 = 168.71 J

1 J= 0.000947817 btu

So Kinetic enrgy lost = 168.71 * 0.000947817 = .16 Btu.