A body of mass 2 kg moving with uniform velocity of `40 ms^(-1)` collides with another body at rest . If two bodies move together with a velocity of ` 20 ms^(-1)` . Find the mass of the other body .

Explanation

Given
Mass of first body , `m_1=2 kg `
Initial velocity of first body , `u_1=40 ms^(-1)`
Final velocity of second body `, u_2=0`
Final velocity of first body , `v_1z=` Final velocity of the second body `,v_2` i.e., `v_1=v_2=20 ms^(-1)`
To find : Mass of second body , `M_2=?`
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=v_1m_1+m_2v_2`
`2 xx 40 + m_2 xx 0= 20 xx 2+ 20 m_2 `
`80 = 40 +20 m_2`
`20 m_2=40 implies `
`m_2=(40)/(20)=2 kg `
Mass of second body , `m_2=2 kg `