# Assuming that the Earth's moon is at an instance 382,000,000m away from the centre of the earth, what are its linear speed and the period of orbit at motion around the earth?

## Answer

The equation for orbital velocity is v = Square Root (GM / r)

Where v is the linear velocity

G is the gravitational constant

M is the mass of the Earth

and r is the distance from the Earth to the satellite (the Moon in this case) = 382 x 10^6 metres

So look up values for G & M, plug them into the equation you'll get an answer.

Also v = rw = but w = 2PI/T

where w is the angular velocity

and T is the period of orbit,

So substituting gives

v = r(2PI/T)

And rearranging

T = r2PI/T or T = 2PIr/v

substitute the values r = 382 x 10^6 and v calculated previously to get T

Updated on March 16, 2018

### Original Article:

By Eugene Brennan