Question

It is raining at $20$ m/s in still air. Now a wind starts blowing with speed $10$m/s in north direction. Ifa cyclist starts moving at $10$ m/s in south direction, then the apparent velocity of rain with respect t cyclist is

• A. $20$m/s
• B. $20\sqrt{2}$
• C. $10\sqrt{5}$ m/s
• D. $30$ m/s

Answer 1

The correct option is C $10\sqrt{5}$ m/s

Then the apparent velocity of rain with respect to a cyclist is

${\overrightarrow{V}}_{apparent}={\overrightarrow{V}}_{wind}+{\overrightarrow{V}}_{cyclist}$

${\overrightarrow{V}}_{apparent}=20i-10j$

the magnitude of apparent velocity

$=10\surd 5\frac{m}{s}$