Question

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.
5. If the value of T is 4 s, then the time after which A will meet B is

A. 12 s
B. 6 s
C. 8 s
D. data insufficient

Answer 1

Correct Answer - C
`u_A=a_AT=u_B-a_BT`
Putting `T=4s`
we get `4(a_A+a_B)=u_B-u_A…..(i)`
Now, `S_A=S_B`
`:. u_At+1/2a_At^2=u_Bt-1/2a_Bt^2`
`:. t=2(u_B-u_A)/(a_A+a_B)=2xx4=8s`