Question

A body of 85kg moving with velocity of 9ms-¹ hits a stationary body of mass 60kg. If the two bodirs stick together after collision, calculate the magnitude of the velocity with whicj they move.

Answer 1

Given:

$m_1=85\:\rm kg$

$v_1=9\:\rm m/s$

$m_2=60\:\rm kg$

$v_2=0\:\rm m/s$

The law of conservation of the momentum says

$$m_1v_1+m_2v_2=(m_1+m_2)v_3$$

Hence, the final velocity of system

$$v_3=\frac{m_1v_1+m_2v_2}{m_1+m_2}$$

$$v_3=\frac{85*9+60*0}{85+60}=5.3\:\rm m/s$$