# Physics gravitational questioonneed help

I need a help.

Find the point where the gravitational force from the earth is 2 times of that from moon.

Andrew Mason
Homework Helper
I need a help.

Find the point where the gravitational force from the earth is 2 times of that from moon.
What is the force of gravity at a point Re from the centre of the earth? What is the force of gravity at a point Rm from the centre of the moon? What is Rm at a point on a line between the centres of the earth and moon that is Re from the centre of the earth?

AM

only the mass of earth, mass of moon and radius of moon and earth is given.
mass of earth=5.98*10(to the power of 24)
mass of moon=7.35*10(to the power of 22)
radius of earth and moon=3.84*10(to the power of 8)

Andrew Mason
Homework Helper
only the mass of earth, mass of moon and radius of moon and earth is given.
mass of earth=5.98*10(to the power of 24)
mass of moon=7.35*10(to the power of 22)
radius of earth and moon=3.84*10(to the power of 8)
The distance between the centres of the earth and moon is 3.84 x 10^8 m or 3.84 x 10^5 km.

Just use Newton's law of universal gravitation to express the force of gravity from the earth at a distance R from the centre of the earth (R>radius of the earth). Same for the moon. Then set the force of gravity of the earth equal to twice the force of gravity of the moon.

AM