Question

Two cars (A) and (B) travel in straight line . The distance of (A) from the starting point is given as a function of time be ` a_A (t) = pt + qt^2 `, with ` p = 2 . 60 ms^(-1)` and ` q= 1.20 ms^(-2)`. The distance of (B) from the starting pint is ` x_B (t) = rt^2 - st^3 ` are ` r= 2. 80 ms^(-2)` and ` s = 0.20 ms^(-3)`. Answer the following questions ,
At what time (s) do the cars (A) and (B) have the same acceleration ?
A. ` 2. 6 7 s`
B. ` 6 . 27 s`
C. ` 4. 33 s`
D. both ` 6. 27 ` and ` 4.33 s`

Answer 1

Correct Answer - A
For the same acceleration , ` a_A=a_B`
` :. 2 q =2 r-6 st`
` t= (r-q)/(3 s) = (2 . 80 - 1. 20 )/( 3 xx 0. 20) = 2 . 67 s`.