Net gravitational force on ball A from balls B and C

[bigtymer8700]

Homework Statement

Each ball weighs 3.00 kg A is 10cm from C to the left and B is 40cm to the right of A

Homework Equations

F=Gm1m2/r^2

The Attempt at a Solution

ive tried adding the forces that each ball apply to A and subtracting it. i know each has its own force acting on A but don't know how to figure it out with 3 objects

 

[Kurdt]

Force is a vector. You have two force acting in opposite directions on ball A. How would you work out the net force then?

 

[bigtymer8700]

Well you already know that each force is acting in the x direction and with gravity the farther away the less the gravitational force so wouldn't you just have to subtract the sum of each force?

 

[bigtymer8700]

F=6.67e-11 (3kg) (3kg))/.04^2 i calculated that for the force of B on A and i got 3.75e-7N

for force of C on A i got 6.003e-7N. Now each of these balls is exerting its own force on A but one is stronger than the other because of the distance so isn't the net force just calculated by the difference?

 

[Kurdt]

If you have to calculate the net force on A then both balls B and C are to the right of it and the forces will add. I was a bit unsure which ball you were wanting to calculate the net force on. The description of the system was a bit ambiguous as well.

 

[bigtymer8700]

In the picture given to me Ball C is to the left of A and ball B is to the right they are on different sides sorry if the description was hazy.