Question

Boxes A and B are in contact on a horizontal, frictionless surface. Box A has mass 20.0 kg and box B has mass 5.0 kg. A horizontal force of 100 N is exerted on box B. What is the magnitude of the force that box B exerts on box A

Answer 1

Box B exerts a force of 100 N on box A, equal to the horizontal force applied to box B, in accordance with Newton's Third Law of Motion on the frictionless surface.

Step-by-step explanation:

When a horizontal force of 100 N is exerted on box B, which is in contact with box A on a frictionless surface, the force that box B exerts on box A will be the same 100 N due to Newton's Third Law of Motion, which states that every action has an equal and opposite reaction. Since the surface is frictionless, there is no force opposing the 100 N exerted on box B; therefore, box B will push against box A with the exact same force.

Answer 2

80 N

Step-by-step explanation:

For A + B: the net force is 100 N = (mA + mB)*a

a = 100/(20 + 5) = 100/25 = 4 m/s²

For A, the net force = mA * a = 20 * 4 = 80 N