# Question #eb544

##### 1 Answer

Nov 2, 2016

Satellite moves faster in orbit when it is close to the planet it orbits, and slower when it is farther away.

#### Explanation:

The satellite experiences two forces while in orbit

- Force due to gravity
#F_g# of the planet

#F_g=G(M_pxxm_s)/R_O^2#

where,#M_p and m_s# are mass of the planet and mass of the satellite respectively;#G# is Universal gravitational constant and#R_O# is the radius of the orbit measured from the center of the planet.

We also know that#R_O=R_p+h# , where#R_p# is the radius of planet and#h# is the height of the satellite above planet's surface. - Net centrifugal force
#F_C# due to its circular motion

#F_C=(m_sv^2)/R_O#

where#v# is the velocity of the satellite.

As the satellite-planet system is in equilibrium, equating both forces we get

From above equation it is evident that when a satellite is moved to a larger radius/higher from the planet’s surface,

**Heights of satellites above earth and their velocities**.