Help with gravitation of forces

In summary, the two objects with a total mass of 5kg attract each other with a gravitational force of 1*10^-8 N when separated by 20 cm. Using the equation Fg=G*m1*m2/r^2, the product of the masses is found to be 5.997kg. Since the sum of the masses is also known to be 5kg, two equations can be formed to solve for the individual masses, which are m1*m2=5.997 and m1+m2=5. By solving these equations, the masses of the two objects can be determined to be approximately 2.45kg and 2.55kg.
  • #1
cougarsoccer
12
0

Homework Statement


Two objects attract each other with a gravitational force of magnitude of 1*10^-8 N when separated by 20 cm. if the total mass of the two objects is 5kg, what is the mass of each.


Homework Equations


Fg=G*m1*m2/r^2


The Attempt at a Solution


i know everything that has to plugged into the equation, but the only part that is hard for me is that it gives you the total sum of the two objects and in the equation, you have to use the product of the masses. how can i change the formula to make it so that i can use the total sum instead of the product?
 
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  • #2
You seem to be stating it the wrong way round. You got the product, (you tell us)! You are given the sum!

From those two you should be able to work out m1 and m2.
 
  • #3
ok i see what you are saying but something just ain't clicking yet. i used what i was given to find the product of m1 and m2:

1x10^-8=(6.67x10^-11)(mtotal/.2^2)
mtotal=5.997kg

so now i have the sum of the two masses and the product of the two.
so if i took the square root of 5.997 you get 2.49 kg. if you add 2.45+2.45 you get 4.9. which is close to 5(prob just cause of round issues) so is that the right way?
 
  • #4
cougarsoccer said:
1x10^-8=(6.67x10^-11)(mtotal/.2^2)
mtotal=5.997kg
What you call "mtotal" is really m1*m2. So m1*m2 = 5.997 is one equation.

But you also know that: m1 + m2 = 5.

Combine those two equations.
 
  • #5
I haven't checked your calculation, but if and when it is right you have got the product. And you already had the sum.

Write down what these two things are as two equations and you may see how to proceed.
 
  • #6
alright i figured it out guys. thanks a lot
 

Related to Help with gravitation of forces

1. What is gravitation of forces?

Gravitation of forces is a fundamental physical phenomenon that describes the attraction between two objects with mass. It is the force responsible for keeping planets in orbit around the sun and objects on Earth from floating off into space.

2. How does gravitation of forces work?

Gravitation of forces works based on the principle of mass attracting mass. Every object with mass exerts a gravitational force on every other object with mass. This force is directly proportional to the mass of the objects and inversely proportional to the square of the distance between them.

3. What is the formula for calculating gravitation of forces?

The formula for calculating gravitation of forces is F = G(m1m2)/r^2, where F is the force of gravity, G is the gravitational constant, m1 and m2 are the masses of the two objects, and r is the distance between them.

4. How does the distance between two objects affect gravitation of forces?

The distance between two objects directly affects the strength of the gravitational force between them. As the distance between two objects increases, the gravitational force decreases, and vice versa. This is because the force of gravity follows an inverse square law.

5. What are some real-world examples of gravitation of forces?

Some real-world examples of gravitation of forces include the orbit of the Earth around the sun, the moon orbiting around the Earth, and the attraction between objects on Earth due to gravity. Other examples include the formation of galaxies, the tides caused by the moon's gravitational pull, and the motion of satellites around the Earth.

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