Question

Two cars A and B at rest at same point initially. If A starts with uniform velocity of 40 m/sec and B starts in the same direction with constant acceleration of $4m/s^{2}$, then B will catch A after how much time

• A. 10 sec
• B. 20 sec
• C. 30 sec
• D. 35 sec

Answer 1

Answer: (B)

20 sec

Answer 2

Let A and B will meet after time t sec. it means the distance travelled by both will be equal.

$S_{A} = ut = 40t$ and $S_{B} = \frac{1}{2}at^{2} = \frac{1}{2} \times 4 \times t^{2}$

$S_{A} = S_{B} \Rightarrow 40t = \frac{1}{2}4t^{2} \Rightarrow t = 20$sec