Definition of Force Inertia and First Law: Practice Problem & Solution
A 1 kg object strikes a wall with velocity \(1 \text{ms}^{-1}\) 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 s, then the force exerted on the wall is
Solution Explained:
To solve this problem, we apply the core principles of Definition of Force Inertia and First Law. Understanding the underlying formula is key to arriving at the correct answer below:
The component of velocity perpendicular to the wall is \(v_n = v sin 60^\circ = \frac{\sqrt{3}}{2} \text{m/s}\). The change in momentum is \(\Delta p = 2 m v_n = 2 \times 1 \times \frac{\sqrt{3}}{2} = \sqrt{3} \text{kg m/s}\). The force is \(F = \frac{\Delta p}{\Delta t} = \frac{\sqrt{3}}{0.1} = 10\sqrt{3} \text{N}\).
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