Question

An inelastic ball falls from a height of 100 meters. It loses $20\%$ of its total energy due to impact. The ball will now rise to a height of:

• A. 80 m
• B. 120 m
• C. 60 m
• D. 9.8 m

Answer 1

Answer: (A)

80 m

The percent loss of Total Energy is given by:
$\%LossofT.E.=\frac{h_1-h_2}{h_1}\times 100$
Here, $\%LossofT.E.=20,h_1=100$m$,h_2=?$
$\Rightarrow 20=\frac{100-h_2}{100}\times 100$
$\Rightarrow h_2=80m$