An artificial satellite is moving in a circular orbit of radius $42250 \mathrm{km}$. Calculate its speed if it takes $24\mathrm{ }\mathrm{hours}$to revolve around the earth.

 An artificial satellite is moving in a circular orbit of radius $42250\mathit{ km}$. 

Speed of $3.079 \mathrm{km}/\mathrm{s}$if it takes $24$hours to revolve around the earth
Here, the radius of the orbit, $\mathrm{r} =42250 \mathrm{km}$
$=42250\times 1000\mathit{ m}$
The time period, $\mathit{T }= 24 h$
$=24\times 60\times 60$
The speed of the satellite, $v=\frac{\mathit{distance}}{\mathit{time}}$
$\Rightarrow v=\frac{2\mathit{\pi r}}{T}$

$=\frac{2\times 3.14\times 42250\times 1000}{24\times 60\times 60}$

$=3070.9 {\mathrm{ms}}^{-1}$

$=3.0709 \mathrm{km}/\mathrm{s}$