Question

A car travelling at 60 km/h overtake another car travelling at 42 km/h. Assuming each car to be 5m long, find the time taken during the overtake and the total road distance used for the overtake.

• A. 2 sec
• B. 1 sec
• C. 10 sec
• D. 5 sec

Answer 1

The correct option is A

2 sec

$v_{\text{A}}=60km/hr=60\times \frac{5}{18}=\frac{50}{3}m/s$
$v_{\text{B}}=42km/hr=42\times \frac{5}{18}=\frac{35}{3}m/s$
$v_{\text{A/B}}=v_{\text{A}}-v_{\text{B}}=\frac{50}{3}-\frac{35}{3}=\frac{15}{3}=5m/s$

Now distance that A travels with respect to B is 10 m. (explained in Hint)

So time taken =$\frac{10}{5}$ = 2 s.