- **Zero Work Examples**
Work is defined as the product of force and displacement in the direction of the force. When either the force or the displacement is zero, the work done is also zero. Here are some examples of zero work:
- **Example 1: Car parked on a street**
When a car is parked on a street, there is no displacement as the car is not moving. Thus, the force required to keep the car stationary does zero work.
- **Example 2: Holding a book in your hand**
When you hold a book in your hand at a certain height, you are applying a force to counteract the gravitational force pulling the book downwards. However, since there is no displacement in the direction of the force, the work done is zero.
- **Example 3: Pushing against a wall**
If you push against a wall with all your might but the wall does not move, no work is done because there is no displacement of the wall in the direction of your force.
- **Not an Example of Zero Work**
- **Example: Lifting a box off the ground**
When you lift a box off the ground, you are applying a force in the upward direction to overcome the gravitational force pulling the box downwards. Since there is a displacement in the direction of the force, work is being done in this case. The work done is equal to the force applied multiplied by the distance the box is lifted.
In conclusion, lifting a box off the ground is not an example of zero work because there is both a force and a displacement involved in this action.