Question

Two objects, P and Q, travelling in the same direction starts from rest. While the object P starts at time $t=0$ and the object Q starts later at $t=30$ min. The object P has an acceleration of $40 \text{ km/h}^2$. To catch P at a distance of $20$ km, the acceleration of Q should be}

• A. $40 \text{ km/h}^2$
• B. $80 \text{ km/h}^2$
• C. $100 \text{ km/h}^2$
• D. $120 \text{ km/h}^2$
• E. $160 \text{ km/h}^2$

Hint:

When objects start at different times, always adjust the effective time before applying motion equations.

Answer 1

Answer: (E)