Positive Work
Positive work occurs when the force applied on an object and the displacement of that object are in the same direction.
- This means that as the force is applied, the object moves forward, gaining energy.
- An example of positive work is pushing a car forward; the direction of the push and the movement of the car are aligned.
- Positive work increases the kinetic energy of the object, making it accelerate.
Negative Work
Negative work takes place when the force applied to an object and its displacement are in opposite directions.
- This implies that the force is acting against the movement of the object, causing it to lose energy.
- An example of negative work is when a person tries to stop a moving car by applying brakes; the brakes exert a force opposite to the direction of motion.
- Negative work decreases the kinetic energy of the object, resulting in deceleration.
Zero Work
Zero work occurs when either the force applied or the displacement is zero, or when the force is perpendicular to the direction of displacement.
- If an object is stationary and no force is applied, or if it moves but no net force is acting on it, then zero work is done.
- An example of zero work is carrying a heavy suitcase while walking horizontally; the gravitational force acts downward, while the displacement is horizontal, resulting in no work done in the direction of motion.
- Other instances include pushing against a wall or moving in a circular path where the force is always perpendicular to the displacement.
Understanding these concepts is crucial in physics, as they explain how energy is transferred and transformed in various situations.