2.7 Work done (energy) and power

Energy is force applied over distance. In our example, let's first figure out how far the Miata needs to accelerate to 60mph.

$D=vt$, where $D$ is distance, $v$ is velocity and $t$ is time. While accelerating, $D=\frac{v^2}{2a}$, where $v$ is the ending velocity. This means $D$ in this case is 80m.

Work done is force (4445N) times distance (80m), so the energy used to accelerate the car is 355600Nm. One Nm is also called a Joule (J). The engine must be able to output 355.6kJ. Since this much energy is converted in 6 seconds, the engine has an output of 59.27kW. This converts to about 79.48 horse power.