Question

A plane is revolving around the earth with a speed of 100 km/hr at a constant height from the surface of earth. The change in the velocity as it travels half circle is

• A. 200 km/hr
• B. 150 km/hr
• C. $100\sqrt{2}km/hr$
• D. 0

Answer 1

Answer: (A)

200 km/hr

Answer 2

$\Delta v = 2v\sin\left( \frac{\theta}{2} \right) = 2 \times v \times \sin 90{^\circ}$

$= 2 \times 100 = 200\mspace{6mu} km ⥂ / ⥂ hr$