Science
Work-energy theorem.
Definition
A principle stating that the net work done on an object equals the change in its kinetic energy. If positive net work is done, the object speeds up; if negative net work is done (such as by friction), the object slows down.
Examples
Real-world.
- 1 A car accelerating from rest — the engine does net positive work, increasing the car's kinetic energy
- 2 A baseball player catching a ball — the glove does negative work, reducing the ball's kinetic energy to zero
- 3 A roller coaster at the bottom of a hill has maximum kinetic energy equal to the work done by gravity during the descent
Key Fact
W_net = ΔKE = ½mv₂² − ½mv₁²