Work-energy theorem — Science definition
The net work done on an object equals its change in kinetic energy: W_net = ΔKE.
Where it is taught
- Work & Power — Work, Energy & Momentum, Physics & Environmental Science, Grade 12
In use
The payoff of tracking work is the work-energy theorem: the net work done on an object equals its change in kinetic energy, W_net = ΔKE.
Work & Power
Questions using work-energy theorem
Problem 1
The net force on a 3.0 kg cart, initially at rest, does 150 J of work on it. Using the work-energy theorem, find the cart's final speed.
Answer and explanation
10 m/s
W_net = ΔKE, so 150 = ½ × 3.0 × v² = 1.5v². Then v² = 100 and v = 10 m/s.