* Work is defined as force applied over a distance.
* When an object moves at a constant velocity, there is no acceleration.
* Newton's Second Law states that force is equal to mass times acceleration (F = ma). Therefore, if there's no acceleration, there's no net force acting on the object.
Let's break it down:
1. You exert a force to lift the object initially. This is work, as you're applying force over a distance to overcome gravity.
2. Once the object is lifted, you exert a force equal to the object's weight to keep it from falling. This force is vertical, but the object is moving horizontally.
3. Since there's no displacement in the direction of the force you're applying, no work is being done.
Example: Imagine carrying a box across a room at a steady pace. You're applying a force to counteract gravity, but since the box is moving horizontally, you're not doing any work in the horizontal direction.
Important Note: While you're not doing work in the strict physics sense, you are expending energy. Your muscles are working to maintain the constant velocity, and you will feel tired. However, this energy expenditure is not considered "work" in a physics context.
