Question

An aeroplane is flying with a uniform speed of 100 km/h along the circumference of a circle. The change in velocity in half the revolution will be (in km/h)

• A. 300
• B. 100
• C. 200
• D. 150

Answer 1

Answer: (C)

Magnitude of velocity($v=100km/h$) is same as given flying with a uniform speed.

In the diagram we can see that direction of velocity changes by ${180}^{\circ }$,so the ultimate change in velocity is given by $\Delta v$

as we can see in the diagram

$v_B={-v}_A$

$\Rightarrow \Delta v={v_A-(-v}_B)\Rightarrow \Delta v=2v_A=2\times 100km/h=200km/h$