Work-Energy Theorem

Core Sentence / 核心句

The net work done on an object equals its change in kinetic energy.

$W_{n e t} = Δ K = \frac{1}{2} m v_{f}^{2} - \frac{1}{2} m v_{i}^{2}$

已知 forces over a displacement，想连接初末 speed，又不需要时间信息时。

左侧是 net work；若改用系统能量账本，必须避免再重复计算已写成 potential-energy change 的 conservative work。