Question

A ball of mass $10g$ moving perpendicular to the plane of the wall strikes it and rebounds in the same line with the same velocity. lithe impulse experienced by the wall is $0.54$ N-s, the velocity of the ball is

• A. $27m{s}^{-1}$
• B. $2.7m{s}^{-1}$
• C. $54m{s}^{-1}$
• D. $37m{s}^{-1}$
• E. $5.4m{s}^{-1}$

Answer 1

The correct option is A $27m{s}^{-1}$

Given,
$\Delta p=0.54N-s$
$m=10\times {10}^{-3}kg$
Impulse $\Delta p=mv-(-mv)$
$\Delta p=2mv$
$0.54=2\times 10\times {10}^{-3}\times v$
$v=\frac{0.54}{2\times {10}^{-2}}$
$\Rightarrow v=\frac{54}{2}$
$v=27m/s$