Question

A body of mass $0.05kg$ travelling with a velocity of $5m/s$ make angle of ${30}^0$ with the wall as shown. The body rebounds with the same speed making an angle of ${30}^0$ with the wall. Find the contact force on the body in $kN$ if the duration of contact is $1ms$.

• A. $0.20$
• B. $0.25$
• C. $0.35$
• D. $0.50$

Answer 1

The correct option is B $0.25$



Change in momemtum is
$\Delta p=m(v-u)=0.05\times (5/2-(-5/2\left)\right)=0.25Ns$
Contact force, $F=\frac{\Delta p}{t}=\frac{0.25}{1\times {10}^{-3}}=0.25kN$