Two blocks are in contact on a horizontal frictionless surface. A 60N constant horizontal force is applied to A. The mass of A is 3.0 kg and the mass of B is 15kg. What is the magnitiure of the force of A on B?

The magnitiure of the force of A on B = 50 N

Explanation:

According to Newton's law of motion,

F = ma

But the m = sum of the masses of block A and block B = 3 + 15 = 18 kg

60 = 18a

a = 3.33 m/s²

This means the two blocks move with the same acceleration, a.

But according to Newton's third law of motion, action and reaction are equal and opposite.

So, the force of A on block B = force of B on block A = mass of block B * acceleration = 15 * 3.33 = 50 N