Question

A fleeing thief is being chased by a police car. If the thief is escaping away at a speed of $25\text{m/s}$ and the police car is covering in $3600\text{m}$ in $3\text{min}$:

• What is the speed of the police car in kmph?
• Will the police be able to overtake the thief?

Answer 1

Given:
The speed of the thief, $s_T=25\text{m/s}$
The police car is travelling $3600\text{m}$ in $3\text{min}$.
In other words, the car is covering $1200\text{m}$ in $1\text{min}$, i.e. its speed, $s_P=1200\text{m/min}$

$1\text{hr}=60\text{min}$ and $1000\text{m}=1\text{km}$

$⟹1200\text{m}=\frac{1200}{1000}=1.2\text{km}$

• The speed of the police car in kmph $=1.2\text{km/min}\times 60\text{min/hr}=72\text{kmph}$

The speed of the police car in m/s will be $72\times \frac{5}{18}=20\text{m/s}$
But the thief is moving at a speed of $25\text{m/s}$.

• Therefore, no! The police cannot be able to overtake/catch the thief if they move at this speed.