A $1 \mathrm{~kg}$ object strikes a wall with velocity $1 \mathrm{~ms}^{-1}$ at an angle of $60^{\circ}$…

A $1 \mathrm{~kg}$ object strikes a wall with velocity $1 \mathrm{~ms}^{-1}$ at an angle of $60^{\circ}$ with the wall and reflects at the same angle. If it remains in contact with wall for $0.1 \mathrm{~s}$, then the force exerted on the wall is
  1. $10 \sqrt{3} \mathrm{~N}$
  2. $20 \sqrt{3} \mathrm{~N}$
  3. $30 \sqrt{3} \mathrm{~N}$
  4. Zero

Solution


$\begin{aligned} & F=\frac{\Delta p}{\Delta t} \\ & \Delta p=2 m v \cos 30^{\circ} \\ & =2 \times 1 \times \frac{\sqrt{3}}{2}=\sqrt{3} \\ & F=\frac{\sqrt{3}}{0.1}=10 \sqrt{3} \mathrm{~N}\end{aligned}$

Asked in: NEET 2023 (Manipur)

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