physics
posted by lanre .
The Moon can be considered to be a sphere with uniform density with mass MM and radius RM. At the (exact) center of the Moon, the gravitational force on a mass m due to the mass of the Moon is?
I know the answer is zero but want to know why using gauss' law

Assume that there is a certain cavity in the center of the Moon where we are going to place the mass ‘m”. Locate the Gaussian closed surface inside the Moon to enclose its central empty region. There will be nothing inside this surface => the flux of gravitational field is zero => the force (which is the product of gravitational field strength and the mass of the object) will be zero.
Respond to this Question
Similar Questions

Physics
A spaceship of mass m travels from the Earth to the Moon along a line that passes through the center of the Earth and the center of the Moon. (a) At what distance from the center of the Earth is the force due to the Earth five times … 
Physics
The average distance separating Earth and the Moon (center to center) is 384 000 km. Use the data in Table 7.3 to find the net gravitational force exerted by Earth and the Moon on a 3.00 multiplied by 104 kg spaceship located halfway … 
Physics
What is the gravitational force on a 93 kg person, due to the moon? 
Science
A spacecraft of mass 500kg lands on the moon. Calculate the moon's gravitational pull on it given that mass of the moon is 7.5 x 10^22kg and radius of the moon is 1.6 x 10^6m. 
Physics
The Earth has a mass of 5.97 x10^24 kg and the Moon has a mass of 7.36 x10^22kg. The average distance between the center of the Earth and the center of the moon is 3.84 x10^8m. (a) How far away would the Moon need to be for the magnitude … 
Physics
A spaceship of mass 175,000 kg travels from the Earth to the Moon along a line that passes through the center of the Earth and the center of the Moon. At what distance from the center of the Earth is the force due to the Earth twice … 
physics
Calculate the magnitude of the gravitational force between the Earth and an m = 6.00 kg mass on the surface of the Earth. The distance to the center of the Earth from the surface is 6.37×103 km and the mass of the Earth is 5.98×1024 … 
physics
The gravitational force that the sun exerts on the moon is perpendicular to the force that the earth exerts on the moon. The masses are: mass of sun=1.99 × 1030 kg, mass of earth=5.98 × 1024 kg, mass of moon=7.35 × 1022 kg. The … 
physics
The gravitational force that the sun exerts on the moon is perpendicular to the force that the earth exerts on the moon. The masses are: mass of sun=1.99 × 1030 kg, mass of earth=5.98 × 1024 kg, mass of moon=7.35 × 1022 kg. The … 
Physics
Many astronomers argue that the Earth and Moon should be considered a double planet,since the gravitational force by the sun on the Moon is approximately as big as that by the Earth on the moon.Using the data below for the Earth and …