the moon takes 27.3 days (2.36x10^6s) to orbit the earth . Calculate its distance from the earth . Take the mass of the earth to be 5.975x10^24kg.

Use the set formula T2=(4Pi^2/GM)R^3 and rearrange for r^3 to give
r3= T2GM/ 4Pi2
then insert values : r3 = (2.36x106)2 x 6.67x10-11x 5.975x1024/ 4PI2 = 5.62....x1025
Then take the cube root of R3 to give 3.830....x108. Question is in 3 sig fig so also give answer in 3 sig fig- so r= 3.83x108m (to 3 s.f) - which is the distance between the centre of the Earth and the centre of the Moon.

Related Physics A Level answers

All answers ▸

How do control rods work in a nuclear fission reactor?


A 100g mass is on a circular turntable spinning at 78 revolutions per minute. The maximum frictional force between the mass and turntable is 0.50N. Find the maximum distance from the center of the turntable at which the mass would stay on the turntable.


What is the most effective use of the equation sheet?


What is the total capacitance of a circuit containing a 3microfarad capacitor and a 2microfarad capacitor in series.