Question

Two cars start off to race with velocities $4m/s$ and $2m/s$ and travel in straight line with uniform accelerations $1m/s^2$ and $2m/s^2$ respectively. If they reach the final point at the same instant, then the length of the path is

• A. $30m$
• B. $32m$
• C. $20m$
• D. $24m$

Answer 1

Answer: (D)

$24m$

$S=4\times 4\times \frac{1}{2}\times 1\times 16$

$=24m$

$S_A=u_{A}t+\frac{1}{2}{a}_A{t}^2$

$S_B=u_{B}t+\frac{1}{2}{a}_B{t}^2$

$4t+\frac{1}{2}\times 1\times t^2=2t+\frac{1}{2}\times 2\times t^2$

$2t=t^2/2,t=45,t=0$