Question

A bus appears to move northwards at a speed of $20\sqrt{3}km{h}^{-1}$, to a man driving his car eastwards with speed $20km{h}^{-1}$. Find the velocity of the bus w.r.t. ground.

Answer 1

Velocity of bus w.r.t. man $\overrightarrow{V_{b,m}}=20\sqrt{3}\hat{j}km/h$

Velocity of man w.r.t. ground $\overrightarrow{V_{m,g}}=20\hat{i}km/h$

Velocity of bus w.r.t. ground $\overrightarrow{V_{b,g}}=\overrightarrow{V_{b,m}}+\overrightarrow{V_{m,g}}$

$⟹\overrightarrow{V_{b,g}}=20\sqrt{3}\hat{j}+20\hat{i}$ $km/h$