Question

A body of mass 2 kg collides with a wall with speed 100 m/s and rebounds with same speed. If the time of contact was 1/50 second, the force exerted on the wall is

• A. 8 N
• B. $2 \times 10^{4}N$
• C. 4 N
• D. $10^{4}N$

Answer 1

Answer: (B)

$2 \times 10^{4}N$

Answer 2

$F = \frac { d p } { d t } = m \frac { d v } { d t } = \frac { m \times 2 v } { 1 / 50 }$ = $\frac { 2 \times 2 \times 100 } { 1 / 50 } = 2 \times 10 ^ { 4 } \mathrm {~N}$