Question

A ball is dropped from a height of 20 cm. Ball rebounds to a height of 10 cm. What is the loss of energy?

• A. 0.25
• B. 0.75
• C. 0.5
• D. 1

Answer 1

Answer: (C)

0.5

Answer 2

Since ball is at a specific height it possess potential energy = mgh where m is mass, g is gravity and h is height Initial energy of ball = mg $h_1$ = 20 mg Final energy of ball = $mgh_2$ =10 mg. Therefore, the loss in energy $\frac{initial\, energy - final\, energy}{initial energy} \times 100$ = $\frac{20mg - 10 mg}{20 mg}\times 100$ =50%