A motor cyclist is riding North in still air at `36 kmh^(-)`-1. The wind starts blowing West ward with a velocity `18 kmh^(-)` ?
If the wind velocity becomes `36 kmh^(-1)` due West, then how much more distance the motor cyclist would cover in 10 min?

Options

A. `2.4 km`
B. `1.8 km`
C. `3.6 km`
D. `8.5 km`

Answer

B

Explanation

New apparent velocity `R.= sqrt(10^(2)+10^(2))=10 sqrt(2) ms^(-1)`
Distance covered `s.=(10 sqrt(2))(10xx60)m=6 sqrt(2)km =8.5km`
Extra distance covered `8.5-6.7=1.8 km`