Three particles far away from any other objects are located on a straight line. The masses of these particles are ma = 363kb, mb= 517 kg, and mc = 154kg. Find the magnitude and direction of the net graviational force actiong on particle a, particle b, and particle c. The distance between a and b is .500m from center point to center point. And the distance between b and c is .250m. F = G * M * m/r^2 do i just solve it using the equation above. F = G * 363 * 517 / .250^2. If so, how do i figure out the direction if it is on a line.