Three Particles - Gravitational Force

Student3.41

1. The problem statement, all variables and given/known data

The masses of these particles are mA = 379 kg, mB = 500 kg, and mC = 140 kg. d1 = 0.558 m and d2 = 0.279 m. Calculate the magnitude of the net gravitational force acting on particle A

(Attached Diagram of Particles.)

2. Relevant equations

F=Gm1m2/r^2

G=6.673x10^-11Nm^2/kg^2

3. The attempt at a solution

The question asks what is the magnitude of the g force acting on particle A. So, I added the masses of particles b and c.

Particle B and C = 640kg

F = (6.673x10^-11)(379kg)(640kg)/(0.558m+0.279m) = (0.0000162)/(0.701)= 0.0000231N (WRONG)

Then I thought particle C has no effect on the force of particle A so I just used the mass of particle A and B.

F=(6.673x10^-11)(379)(500)/(0.558)^2 = (0.0000126)/(0.346) = 0.0000364N

Then I added the Force from A-B and Force B-C...

Fa-b=0.0000364N

Fb-c=(6.673x10^-11)(500)(140)/(0.279)^2 = 0.0000600N

Therefore, 0.0000364N+0.0000600N=Fnet=0.0000964N

Can anyone help????

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Related Introductory Physics Homework News on Phys.org

Find the force on A due to B on on its own then A due to C on its own.Both forces on A act in the same direction so to find the total force just add them.

tiny-tim

Homework Helper
Hi Student3.41! The question asks what is the magnitude of the g force acting on particle A. So, I added the masses of particles b and c.

Particle B and C = 640kg

F = (6.673x10^-11)(379kg)(640kg)/(0.558m+0.279m) = (0.0000162)/(0.701)= 0.0000231N (WRONG)
You can't do that!!

You must add the force from B to the force from C (ie, use the formula twice, separately) …

you can't just add the masses, and add the distances, and then chuck them all into the same formula! Try again. Student3.41

Thank you!, got to analyze the problem more Physics Forums Values

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