Question

A car 4m long moving at a velocity of 25ms/1 was beside a lorry 20m long with a velocity of 19m/s. The distance between them is 10m. How long will it take the car to overtake the lorry.

Answer 1

Let L - the length of the lorry;

l - the length of the car;

d - the distance between them;

V - the velocity of the lorry;

v - the velocity of the car.

The car will overtake the lorry, when the distance traveled by car in time t will be more than the distance traveled by lorry by $L+d+l.$

So,

$vt-Vt=L+d+l,$

$t=\frac{L+d+l} {v-V}=\frac{20+10+4} {25-19} \approx 5.7\space s.$

Answer: 5.7 s.