Question

A car travelling at a constant speed of $10m/s$ on a straight road passes a point (origin) at time $t=0$, and $5$ seconds later another car passes the same point travelling at $20m/s$ in the same direction.
The time $t$ (from starting time) and distance from origin $x$, when second car overtakes first?

• A. $t=10$ seconds
• B. $x=100$ meter
• C. $t=8$ seconds
• D. $x=80$ meter

Answer 1

Answer: (A), (B)

$t=10$ seconds
$x=100$ meter

distance traveled with constant velocity $S=v.t$

1st car travels $S_1=10t$

second car starts after 5 s therefore

$S_2=20(t-5)$

when they meet both distance traveled by cars should be equal

$10t=20(t-5)$

$t=10s$

$S_1=S_2=100meters$