Question

In the elastic collision of heavy vehicle moving with a velocity 10 ms${}^{-1}$ and a small stone at rest, the stone will fly away with a velocity equal to :

• A. 40 ms${}^{-1}$
• B. 20 ms${}^{-1}$
• C. 10 ms${}^{-1}$
• D. 5 ms${}^{-1}$

Answer 1

The correct option is B 20 ms${}^{-1}$

In the elastic collision between a heavy object and a very light object at rest, the velocity of particles after collision is
for heavy particle, $v_1=u_1$
for light particle, $v_2=2u_1-u_2$
since, $u_2=0$ hence,
$v_2=2u_1$
Therefore, the stone will fly away with a velocity equal to
$v_2=2u_1=2\left(10\right)=20m{s}^{-1}$