Three blocks are initially placed as shown in the figure. Block A has mass m and initial velocity v to the right. Block B with mass m and block C with mass 4 m are both initially at rest. Neglect friction. All collisions are elastic. The final velocity of block A is

Options

A. `0.6v` to the left
B. `1.4 v` to the left
C. `v` to the let
D. `0.4 v` to the right

Answer

A

Explanation

Since `A` and `B` have same mass. So, after elastic collision they interchange their velocity
`:. v_(B)=v`
After collision takes place between `A` and `B` so, velocity will be inter changed.
`:. v_(A)^(')=(v_(B)^('))=3/5v` in left ward direction.