A spere of mass 20 kg moving with a velocity `40 ms^(-1)` collides with another sphere of mass 15 kg which is at rest . After collision they move with the same velocity . Find the velocity .

Explanation

Given
Mass of the first body , `m_1=20kg `
Mass of the second body , `m_2= 15 kg `
Initial velocity of first body , `u_1=40 ms^(-1)`
Initial velocity of second body , `u_2=0`
( Second body is at rest initially )
Final velocity of the first body , `v_1=` Final velocity of the second body , `v_2`
i.e.,`v_1=v_2=v`
To find : v=?
Solution
According to law of conservation of momentum ,
`m_1u_1+m_2u_2=m_1v_1+m_2v_2`
`m_1u_1+m_2u_2=(m_1+m_2)v`
`20 xx 40 + 15 xx 0 = (20+15)v`
` 800=35v`
Velocity , v=(800)/(35)=22.85 ms^(-1)`