Which of the following options represents the swing equation?
1
\({M} \frac{d^2 \delta}{d t^2}\) = - accelerating power
2
\({M} \frac{d^2 \delta}{d t^2}\) = shaft power
3
\({M} \frac{d^2 \delta}{d t^2}\) = accelerating power
4
\({M} \frac{d^2 \delta}{d t^2}\) = electromagnetic power