Here's why:
* Work is defined as the force applied multiplied by the distance moved in the direction of the force. This is represented by the equation: Work (W) = Force (F) * Distance (d) * cos(theta), where theta is the angle between the force and the displacement.
* If the object doesn't move, the distance (d) is zero. Therefore, regardless of the force applied, the work done will be zero.
* Even if the object moves, but the force is perpendicular to the direction of motion, the angle (theta) will be 90 degrees. Since cos(90°) = 0, the work done will still be zero.
Examples:
* Pushing against a wall: You exert force, but the wall doesn't move, so no work is done.
* Carrying a heavy box horizontally: You exert an upward force to counteract gravity, but the box only moves horizontally. The force is perpendicular to the motion, so no work is done by your upward force.
Let me know if you have any other questions!
