# HW Question, very simple. mass/gravity

• ek378996
In summary, if a planet is half the size of the Earth and has the same gravitational acceleration, its mass would have to be four times larger than the Earth's mass. This can be calculated using the equation Gme / re2 = Gmp / rp2.
ek378996
If a planet is 1/2 of earth, gravitational is the same of earth, what does that tell you about the mass?

ek378996 said:
If a planet is 1/2 of earth

half the size?

anyhow...What is mass affected by?

yes, half the size. Nothing, just trying to find out if the mass of the planets is 2 or 4 times larger/smaller than earth.

basically if a planet is half the size of the earth, and gravitation is the same as earth, what would the planets mass have to be? 2 or 4 times larger than earth?

Last edited:
Greetings:

If acceleration due to gravity is equal for both the Earth and another planet, then,

Gme / re2 = Gmp / rp2.
==> me = (re / rp)2 mp
==> me = (2rp / rp)2 (given re = 2rp)
==> me = 4mp

Regards,

Rich B.
rmath4u2@aol.com

## What is mass?

Mass is a measure of the amount of matter in an object. It is usually measured in kilograms (kg).

## What is gravity?

Gravity is a force that exists between any two objects with mass. It is responsible for the attraction between objects and is what keeps planets in orbit around the sun.

## How does mass affect gravity?

The larger the mass of an object, the stronger its gravitational pull. This means that objects with larger masses will attract each other with a greater force than objects with smaller masses.

## What is the difference between mass and weight?

While mass is a measure of the amount of matter in an object, weight is a measure of the force of gravity acting on an object. This means that an object's weight can change depending on the strength of the gravitational pull, but its mass will remain constant.

## Why is gravity important?

Gravity is important because it is a fundamental force in the universe that affects the motion of all objects. It plays a crucial role in the formation and stability of planets, stars, and galaxies, and it also allows us to stay grounded on Earth.

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