Question

A thief is running away on a straight road on a jeep moving with a speed of $9\text{m/s}$. A police man chase him on a motor cycle moving at a speed of $10\text{m/s}$. If the instantaneous separation of jeep from the motor cycle is $100\text{m}$, how long will it take for the policemen to catch the thief?

• A. 1 second
• B. 19 second
• C. 90 second
• D. 100 second

Answer 1

The correct option is D 100 second

Relative speed of police with respect to thief $=10-9=1\text{m/s}$
Instantaneous sepration $=100\text{m}$
Time to catch the thief, $t=\frac{\text{Instantaneous sepration}}{\text{Relative velocity}}=\frac{100}{1}=100\text{sec}$