physics
posted by abhinaw .
two equal masses of 5kg are placed on two vertex of an an equilateral triangle and 20 kg mass on the third.each side is 20 cm long. find the force acting on 1 kg mass kept at the centroid of the triangle.

It looks like the want you to compute the resultant gravitational force on the centroid mass, due to the three masses at the corners. Use the newton universal law of gravity.