Question

A satellite of mass 200kg is placed into Earth orbit at a height of 200km above the surface.
(a) Assuming a circular orbit, how long does the satellite take to complete one orbit?
(b) What's the satellite's speed?

Answer 1

Answer

b) r=R_e+h

M_e massof earth

In circular motion

Centripetal force is equivalent to gravitational force

$F_c=F_g$

$\frac{mv^2}{r}=\frac{GmM_e}{r^2}$

$v=\sqrt{\frac{GM_e}{r}}$

Putting all value according to the question

$v=7.79\times10^3$ m/s

a) now time taken to complete one orbital motion

$T=\frac{2\pi r}{v}$

Putting value of r and v

T=1.48hrs.