Q. Two cars P and Q start from a point at the same time in a straight line and their positions are represented by $x_P(t) = at + bt^2$ and $x_Q(t) = ft - t^2$. At what time do the cars have the same velocity?
A) $\frac{a - f}{1 + b}$
B) $\frac{a + f}{2(b - 1)}$
C) $\frac{a + f}{2(1 + b)}$
D) $\frac{f - a}{2(1 + b)}$
Explanation
[Solution] $a + 2bt = f - 2t$, so $t = \frac{f - a}{2(1 + b)}$. Answer (4).
Reviewed by Dr. Abubacker
Physics Educator & NEET/JEE Specialist
Ph.D. in Physics with 19+ years of teaching experience.