A 0.10-kilogram ball dropped vertically from a height of 1.0 meter above the floor bounces back to a height of 0.80 meter. The mechanical energy lost by the ball as it bounces is approximately

A) 0.20 J

B) 0.080 J

C) 0.78 J

D) 0.30 J

A) 0.20Joules

Explanation:

The type mechanical energy acting on the body is potential energy since the body is covering a particular height.

Potential Energy = mass*acceleration due to gravity * height

Mass of the body = 0.1kg

acceleration due to gravity = 10m/s²

h is the height of the object when dropping = 1.0meters

Substituting this values in the formula to get the energy of the body on dropping, we have;

PE = 0.1*10*1.0

PE = 1.0Joules

On bouncing back to height of 0.8m, the potential energy becomes

PE = 0.1*10*0.8

PE = 0.8Joules

The mechanical energy lost by the ball as it bounces will approximately be the difference in its potential energy when dropping and when it bounces back i. e 1.0Joules - 0.8Joules = 0.20Joules