Question

An artificial planet is moving in a circular orbit of radius 42250 km. Calculate its speed in km/second if it takes 24 hours to revolve around the earth.

Hint: pi = 3.14

• A. $4.21\frac{km}{s}$
• B. $3.07\frac{km}{s}$
• C. $2.07\frac{km}{s}$
• D. $1.28\frac{km}{s}$

Answer 1

The correct option is B

$3.07\frac{km}{s}$

Speed $=\frac{Circumferenceoftrajectory}{Timeperiod}$

$=\frac{2\pi R}{T}$

$=\frac{2\times \pi \times 42250}{24\times 3600}$ $\frac{km}{s}$
$[\because 1hr=60\times 60=3600s]$

$=3.07\frac{km}{s}$