Work-Energy Theorem Calculator
Find the net work done on an object from its mass and its initial and final speeds using the work-energy theorem.
kg
m/s
m/s
Equal to the change in kinetic energy
- 1
Initial kinetic energy
½ × 2 × 3² = 9 - 2
Final kinetic energy
½ × 2 × 7² = 49 - 3
Net work done
49 − 9 = 40W_net = KE_final − KE_initial — the work-energy theorem.
How does this calculator work?
The work-energy theorem says net work equals the change in kinetic energy: W = ½·m·(v² − u²). Enter mass and the initial and final speeds, and the calculator returns the net work in joules along with the initial and final kinetic energies. Positive work means speeding up; negative means slowing down.
Formula
How this is calculated
The work-energy theorem states that the net work done on an object equals its change in kinetic energy: W_net = ΔKE = KE_final − KE_initial. Enter the mass m in kilograms, the initial speed u in metres per second, and the final speed v in metres per second.
Kinetic energy is computed as KE = ½·m·speed². The calculator finds the initial kinetic energy KE_i = ½·m·u² and the final kinetic energy KE_f = ½·m·v², then reports the net work as W = KE_f − KE_i = ½·m·(v² − u²). Energies and work are expressed in joules (J).
A positive net work means the object sped up (energy was added by the net force); a negative net work means it slowed down. The theorem assumes a single rigid object whose only relevant energy change is translational kinetic energy, and the speeds entered should be magnitudes, since only the square of speed enters the formula. Mass must be non-negative.
Frequently asked questions
It states that the net work done on an object equals the change in its kinetic energy: W_net = KE_final − KE_initial.
When the final speed is less than the initial speed, the object loses kinetic energy, so the net work is negative — the net force opposed the motion.
Only the speed (magnitude of velocity) matters here, because kinetic energy depends on speed squared, not on direction.
Also known as
TG we-Calculate Editorial Team. (2026). Work-Energy Theorem Calculator [Online calculator]. TG we-Calculate. https://we-calculate.com/calculator/work-energy-theorem-calculator
TG we-Calculate Editorial Team. "Work-Energy Theorem Calculator." TG we-Calculate. 2026. https://we-calculate.com/calculator/work-energy-theorem-calculator.
TG we-Calculate Editorial Team, "Work-Energy Theorem Calculator," TG we-Calculate, 2026. [Online]. Available: https://we-calculate.com/calculator/work-energy-theorem-calculator
@misc{wecalculate_work_energy_theorem_calculator, title = {Work-Energy Theorem Calculator}, author = {{TG we-Calculate Editorial Team}}, howpublished = {\url{https://we-calculate.com/calculator/work-energy-theorem-calculator}}, year = {2026}, note = {TG we-Calculate} }
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