Question

A bus is going due north at a speed of $50km/h$. It makes a ${90}^{\circ }$ left turn without changing the speed. The change in the velocity of the bus is

• A. $50km/h$ toward west
• B. $50km/h$ towards southwest
• C. $70.7km/h$ towards southwest
• D. $70.7km/h$ towards northwest

Answer 1

The correct option is C $70.7km/h$ towards southwest

When bus turns ${90}^0$ left, it form an right angle triangle with base and perpendicular as $50km/hr$, so the resultant or change in velocity can be calculated as
change in velocity $\left|\Delta v\right|=\sqrt{{50}^2+{50}^2}=70.7km{h}^{-1}$ and it is along southwest direction .