That is because it is impossible to create a law for the behavior of every single different gas, so creating laws for an ideal gas helps us understand the basic nature of gasses which might or might not differ slightly or a lot. By understanding how an ideal gas works, we can understand how a normal gas works.
Answer:
Explanation:
Given
Force 
one at an angle of 
East of North and another at West of North
Net Force is in North Direction
Forces in horizontal direction will cancel out each other
thus Work done will be by north direction forces
here 
The force depends on the mass of both objects and the distance between them
F = G*m1*m2/r^2
So the force has a linear connection with the mass of both objects and a quadratic connection with the distance between the center of masses
the key result indicate that how you will achieve the your goal
