Three identical masses of 500 kg each are placed on the x axis. One mass is at x_1 = -11.0 cm, one is at the origin, and one is at x_2 = 37.0 cm. What is the magnitude of the net gravitational force F_grav on the mass at the origin due to the other two masses?

Take the gravitational constant to be G = 6.67×10−11 N \m^2/kg^2.
Express your answer in newtons.

1 answer

The two masses at x1 = -11 cm and at x2 = -37 cm apply forces in opposite directions to the mass at the origin.

Use Newton's universal gravity law (which you should know) to compute each of the two forces, and then SUBTRACT them.

The force due to the mass at x1 is

F1 = G (500)^2/(0.11 m)^2