Question

1.   A 1-kg body of velocity 10m/s collides with a 2-kg body which is the rest .After collision, the two stick together. What is the velocity of the two bodies after collision?

 

Answer 1

Given:

$m_1=1\:\rm kg$

$m_2=2\:\rm kg$

$v_1=10\:\rm m/s$

The law of conservation of momentum says

$$m_1v_1=(m_1+m_2)u$$

Hence, the final speed of bodies

$$u=\frac{m_1v_1}{m_1+m_2}=\frac{1*10}{1+2}=3.3\:\rm m/s$$