Vihjed rehkenduseks

Kogu mehaaniline energia, mis kummipael lühenedes autosse ja vankrisse pani:

E_{k} = \frac{m_{a} v_{a}^{2}}{2} + \frac{m_{v} v_{v}^{2}}{2}

Kui stardiplatvorm paigal seisab, läheb kogu see kineetiline energia auto kineetiliseks energiaks. Nii et

E_{k} = \frac{m_{a} v^{2}}{2}

Ja siit

v = \sqrt{\frac{2 E_{k}}{m_{a}}}

Nii et

v = \sqrt{\frac{2}{m_{a}} (\frac{m_{a} v_{a}^{2}}{2} + \frac{m_{v} v_{v}^{2}}{2})}

v_{a} = \frac{m_{v}}{m_{a}} v_{v}

siis

\begin{matrix} v & = \sqrt{\frac{2}{m_{a}} (\frac{m_{a}}{2} {(\frac{m_{v}}{m_{a}})}^{2} v_{v}^{2} + \frac{m_{v} v_{v}^{2}}{2})} = v_{v} \sqrt{\frac{m_{v}}{m_{a}} + {(\frac{m_{v}}{m_{a}})}^{2}} \end{matrix}