The normal force acting on the block is equal to the force of gravity acting on the block. This normal force can be calculated using the formula:

N = mg

where N is the normal force, m is the mass of the block, and g is the acceleration due to gravity.

The force of gravity acting on the block can be calculated using the formula:

Fg = mg

where Fg is the force of gravity, m is the mass of the block, and g is the acceleration due to gravity.

The force of gravity can be resolved into two components: one parallel to the inclined plane and one perpendicular to the inclined plane. The component parallel to the inclined plane is given by:

Fp = mg * sinθ

where Fp is the force parallel to the inclined plane, m is the mass of the block, g is the acceleration due to gravity, and θ is the slope angle of the inclined plane.

The component perpendicular to the inclined plane is given by:

Fn = mg * cosθ

where Fn is the force perpendicular to the inclined plane, m is the mass of the block, g is the acceleration due to gravity, and θ is the slope angle of the inclined plane.

The force parallel to the inclined plane is the force that causes the block to slide down the plane, while the force perpendicular to the inclined plane is the force that keeps the block in contact with the plane.

To calculate the force required to keep the block in equilibrium on the inclined plane, we need to consider the forces acting on the block. If there is no acceleration, the sum of the forces in the direction perpendicular to the inclined plane must be zero. Therefore, the force required to keep the block in equilibrium is equal to the force perpendicular to the inclined plane:

F = Fn

where F is the force required to keep the block in equilibrium, and Fn is the force perpendicular to the inclined plane.

In summary, the force required to keep the block in equilibrium on an inclined plane with a slope angle θ is equal to the force perpendicular to the inclined plane, which can be calculated using the formula:

F = mg * cosθ