Work-energy theorem

When there’s no energy waste (no work nor heat transferred out of the system), the sum of all work $W_\text{all}$ done by all forces causes the change in kinetic energy $K$.

$$W_\text{all}=\Delta K$$

Here, the work $W_\text{all}$ contains that of both non-conservative and conservative forces (the latter will usually be excluded from $W$ and instead added as potential energies $U$).