What is zero work?

Zero work refers to a situation where no energy is transferred or exerted on an object, resulting in no change in its motion or position. In other words, it's when no force is applied to an object, or the force is applied perpendicular to the direction of motion. To understand this, let's use a few examples. Imagine pushing a car that is parked on a flat road. If you push the car horizontally, parallel to the road, your force is doing work, as it causes the car to move and covers a certain distance. However, if you push the car vertically, upward or downward, your force will be perpendicular to the direction of motion, resulting in zero work. This is because the force you exert does not contribute to the car's displacement or change in its position. Similarly, if you hold a heavy object and walk in a straight line without changing the height, no work is being done. In this case, you might be applying a force to hold the weight, but since there is no displacement in the direction of the force, the work done is zero. Another example is lifting a book and carrying it while keeping it at the same height. Although you need to exert a force to counteract gravity, the book doesn't move vertically, so the work done is again zero. In summary, zero work occurs when the force applied is perpendicular to the motion or when there is no displacement in the direction of the force. This means that no energy is transferred or used to change the object's position or motion.