100 balls each of mass m moving with speed v simultaneously strike a wall normally and reflected back with same speed, in time t s. The total force exerted by the balls on the wall is

Question

100 balls each of mass m moving with speed v simultaneously strike a wall normally and reflected back with same speed, in time t s. The total force exerted by the balls on the wall is (A) (100 m v/t) (B) 200 m v t (C) (200 m v/t) (D) (m v/100 t)

Tardigrade Admin · Accepted Answer

P i = Nm ∪ hat i vec P f =- Nm v hat i N is Number of balls strikes with wall N =100 Δ vec P = vec P f - vec P i =-2 Nm v hat i =-200 Nm hat hati vec F text Total =(Δ vec P /Δ t )=-(200 mvt / t ) | vec F |=(200 mv / t )

Q. $100$ balls each of mass $m$ moving with speed $v$ simultaneously strike a wall normally and reflected back with same speed, in time $t s$ . The total force exerted by the balls on the wall is

$\frac{100 m v}{t}$

$200 m v t$

$\frac{200 m v}{t}$

$\frac{m v}{100 t}$

$P_{i} = N m \cup \hat{i} P_{f} = - N m v \hat{i}$
$N$ is Number of balls strikes with wall
$N = 100$
$Δ P = P_{f} - P_{i} = - 2 N m v \hat{i}$
$= - 200 N m \hat{\hat{i}}$
$F_{Total} = \frac{Δ P}{Δ t} = - \frac{200 m v t}{t}$
$∣ F ∣ = \frac{200 m v}{t}$

Q. 100 balls each of mass m moving with speed v simultaneously strike a wall normally and reflected back with same speed, in time ts. The total force exerted by the balls on the wall is

t100mv​

200mvt

t200mv​

100tmv​