n balls each of mass m impinge elastically each second on a surface with velocity u. The average force experienced by the surface will be

Question

n balls each of mass m impinge elastically each second on a surface with velocity u. The average force experienced by the surface will be (A) mnu (B) 2 mnu (C) 4 mnu (D) mnu/2

Tardigrade Admin · Accepted Answer

Change in momentum of one ball =2 m u, time taken =1 s F av =( text Total change in momentum / text Time taken ) =(n(2 m u)/1)=2 m n u

Q. $n$ balls each of mass $m$ impinge elastically each second on a surface with velocity $u$ . The average force experienced by the surface will be

mnu

2 mnu

4 mnu

mnu/2

Change in momentum of one ball $= 2 m u$ , time taken $= 1 s$
$F_{a v} = \frac{Total change in momentum}{Time taken}$
$= \frac{n ( 2 m u )}{1} = 2 mn u$

Q. n balls each of mass m impinge elastically each second on a surface with velocity u. The average force experienced by the surface will be

mnu

2 mnu

4 mnu

mnu/2

Change in momentum of one ball =2mu, time taken =1s Fav​= Time taken Total change in momentum ​ =1n(2mu)​=2mnu

Q. $n$ balls each of mass $m$ impinge elastically each second on a surface with velocity $u$ . The average force experienced by the surface will be

Change in momentum of one ball $= 2 m u$ , time taken $= 1 s$
$F_{a v} = \frac{Total change in momentum}{Time taken}$
$= \frac{n ( 2 m u )}{1} = 2 mn u$