A situation is shown in which two objects A and B start their motion from same point in same direction. The graph of their velocities against time is drawn. `u_A and u_B` are the initial velocities of A and B respectively. T is the time at which their velocities become equal after start of motion. You cannot use the data of one question while solving another question of the same set. So all the questions are independent of each other.
6. Let `v_A and v_B` be the velocities of the particles A and B respectively at the moment A and B meet after start of the motion. If `u_A = 5 ms^-1 and u_B = 15 ms^-1,` then the magnitude of the difference of velocities `v_A and v_B` is

Options

A. `5 ms^-1`
B. `10 ms^-1`
C. `15 ms^-1`
D. data insufficient

Answer

B

Explanation

`S_A-S_B`
`5t+1/2a_At^2=15t-1/2a_Bt^2`
or `10+a_At=30-a_Bt`
`:. (5+a_At)-(15-a_Bt)=10`
or `v_A-v_B=10 m//s`