NTA Abhyas JEE Main2020PhysicsMotion in One DimensionPractice
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 = a t + b t 2 and X Q t = f t - t 2 . At what time do the cars have the same velocity?
Options
- Aa - f 1 + b
- Ba + f 2 b - 1
- Ca + f 2 1 + b
- Df - a 2 1 + b
Correct answer
D. f - a 2 1 + b
Step-by-step solution
v P = d x P d t = a + 2 b t v Q = d x Q d t = f - 2 t v P = v Q ⇒ a + 2 b t = f - 2 t 2 t + 2 b t = f - a ⇒ t = f − a 2 ( b + 1 )