A 40 kg slab rests on a frictionless floor – what forces act on it?

When a 40 kg slab rests on a frictionless floor, only a few forces act on it because there is no friction.

Forces acting on the slab:

• Weight (mg):
  Acts vertically downward due to gravity
  Weight = m × g = 40 × 9.8 = 392 N
• Normal reaction (N):
  Acts vertically upward from the floor

Since the slab is at rest and the floor is frictionless:

• Net force = 0
• Normal force (N) = Weight (mg)

So,
N = 392 N

Key points:

• No frictional force acts because the surface is frictionless
• Only vertical forces are present
• The slab remains in equilibrium