Question

If n balls hit elastically and normally on a surface per unit area and all units has mass m and are moving with same velocity u, then force on surface is:

• A. $mun$
• B. $2mun$
• C. $\frac{1}{2}m{u}^{2}n$
• D. $m{u}^{2}n$

Answer 1

The correct option is B $2mun$

Impulse acting per second = 2 n m u

F.T = 2 n m u

F = 2 n m u