Question

A metal ball falls from a height of 1 m on to a steel plate and jumps upto a height of 81 cm. The coefficient of restitution of the ball material is?

• A. 0.2
• B. 9
• C. 0.9
• D. 90

Answer 1

The correct option is C 0.9

The correct option is C

Given

Since $v=\sqrt{(}2as)=\sqrt{(}2gs)$

here $g=9.8m/s^2$

vfor a 1 m is $\sqrt{1}9.2$

v for a .81 m bounce is (81 cm=.81 m)

$\sqrt{(}.81\times 19.2)$=$0.9\sqrt{1}9.2$

so the cofficient restitution is 0.9