Q. 10000 small balls, each weighing 1 g, strike one square centimeter of area per second with a velocity ${100\ ms}^{- 1}$ in a normal direction and rebound with the same velocity. The value of pressure on the surface will be
A) $2 \times 10^{3}\ {Nm}^{- 2}$
B) $2 \times 10^{5}\ {Nm}^{- 2}$
C) $10^{7}\ {Nm}^{- 2}$
D) $2 \times 10^{7}\ {Nm}^{- 2}$
Explanation
(d) Pressure
$p = \frac{F}{A} = \frac{n\left\{ mv - (mv) \right\}}{A} = \frac{2mnv}{A}$
$= \frac{2 \times 10^{- 3} \times 10^{4} \times 10^{2}}{10^{- 4}} = 2 \times 10^{7}\ {Nm}^{- 2}$
Reviewed by Dr. Abubacker
Physics Educator & NEET/JEE Specialist
Ph.D. in Physics with 19+ years of teaching experience.