Use Newton's universal law of gravity
F = G M1*M2/R^2 to get the mass product M1*M2. G is the universal constant, which you should look up.
You also know that M1 + M2 = 4.0 kg
Knowing both the product and the sum of the masses, you can get the individual masses using algebra.
How to solve/work problem?
Two objects attract each other gravitationally with a force of 2.5 * 10^-10 N when they are .25m apart. Their total mass is 4.0kg. Find their individual masses.
2 answers
So do you take 2.5*10^-10N (4.0)/.25^2?