The figure shown the velocity as a function of the time for an object with mass `10kg` being pushed along a frictioniess horizontal surface sby external horizontal force. At `t=3s`, the force stops pushing and the object moves freely. It then collides head on and sticks to another object of mass `25g`

Options

A. External force acting on the system is `50 N`
B. Velocity of the `2^(nd)` particle just before the collision is `1 m//s`
C. Before collision both bodies are moving in the same direciton
D. Before collision, bodies are moving in opposite direction with respect to each other

Answer

A, B, C

Explanation

`F_(ext) = (Delta(mv))/(Deltat) = (10 xx (15 - 0))/(3) = 50N`
`COLM : m_(1)u_(1)+ m_(2)u_(2) = (m_(1) + m_(2))v`
`rArr 10 xx 15 + 25 xx u_(2) = (10 + 25)5 rArr u_(2) = 1 m//s`