* Gravity acts vertically: Gravity always pulls objects downwards towards the center of the Earth. It doesn't exert a force in the horizontal direction.
* Work is force times displacement: Work is done when a force causes an object to move a certain distance. The formula is: Work = Force x Displacement x cos(theta)
* 'theta' is the angle between the force and the displacement.
* Horizontal motion and gravity are perpendicular: Since the force of gravity acts vertically and the displacement is horizontal, the angle between them is 90 degrees.
* Cosine of 90 degrees is zero: Therefore, cos(90) = 0, making the work done against gravity zero.
In simpler terms:
Imagine pushing a box across a frictionless floor. You're doing work against friction (if there was any), but not against gravity. Gravity is trying to pull the box down, but since you're moving it horizontally, there's no 'battle' against gravity.
