A body of mass 3 kg is moving with a velocity of `4ms^(-1)` towards right, collides head on with a body of mass 4 kg moving in opposite direction with a velocity of `3ms^(-1)` . After collision the two bodies stick together and move with a common velocity, which is

Options

A. zero
B. `12 ms^(-1)` towards left
C. `12 ms^(-1)` towards right
D. `12/7 ms^(-1)` towards left

Answer

A

Explanation

`m_1u_1 + m_2u_2 = (m_1 + m_2)v implies 3 xx 4 + 4 xx (-3) = (3 + 4) v " " therefore v = 0`