Question

A 500 g ball is released from a height of 4 m. Each time it makes contact with the ground it loses 25% of its energy. Find the KE it possess after 3^rd hit :

• A. 15 J
• B. 11.25 J
• C. 8.44 J
• D. None of these

Answer 1

Answer: (C)

8.44 J

Answer 2

After first hit K.E₁ = e² K.E

3/4 K.E = e² K.E Ž e² = 3/4

K.E. after third hit = e²⁽³⁾. K.E = 27/64 (mgh)

=

= 27$\left( \frac { 5 } { 16 } \right) = \frac { 135 } { 16 }$ = 8.44 J