Gravitational constant (G)

Normal forces: Normal forces are contact forces exerted by a surface to support an object resting on it. They act perpendicular to the surface and counterbalance external forces.

Frictional forces: Frictional forces are resistive forces that oppose motion when two surfaces are in contact with each other. They can be either static or kinetic, depending on whether there is relative motion between the surfaces.

Weight: Weight is the force experienced by an object due to gravity. It depends on both mass and acceleration due to gravity and is given by W = mg, where m is mass and g is acceleration due to gravity.