1. No Force:
* If there is no force acting on an object, there can be no work done, regardless of motion.
2. No Displacement:
* If an object is stationary, or if the force applied does not cause any movement, no work is done. Think of pushing against a wall – you might exert force, but since the wall doesn't move, no work is done.
3. Force Perpendicular to Displacement:
* This is the key point! When the force and the displacement are perpendicular to each other, no work is done.
* Example: Imagine carrying a heavy box horizontally across a room. You are applying a force upwards to counteract gravity (to keep the box from falling), but the box is moving horizontally. Since your force is perpendicular to the direction of motion, no work is being done by your upward force.
Key Formula:
* Work (W) = Force (F) × Displacement (d) × cos(θ)
* θ is the angle between the force and displacement vectors.
* When θ = 90° (perpendicular), cos(90°) = 0, and therefore Work = 0
In Summary:
Work is done when a force causes a displacement in the direction of the force. If there is no force, no displacement, or if the force is perpendicular to the displacement, no work is done.
