- Average total energy per cycle is equal to its maximum kinetic energy.
- Average kinetic energy per cycle is equal to half of its maximum kinetic energy.
- Root mean square velocity is $\frac{1}{\sqrt{2}}$ times of its maximum velocity.
Explanation:
In case of S.H.M, average total energy per cycle
= Maximum kinetic energy (K0)
= Maximum potential energy (U0)
Average KE per cycle $=\frac{0+\text{K}_0}{2}=\frac{\text{K}_0}{2}$
Let us write the equation for the SHM $\text{x}=\text{a}\sin\omega\text{t}.$
Clearly, it is a periodic motion as it involves sine function.
Let us find velocity of the particle, $\text{v}=\frac{\text{dx}}{\text{dt}}=\frac{\text{d}}{\text{dt}}(\text{a}\sin\omega\text{t})=\text{a}\omega\cos\omega\text{t}$
Mean velocity over a complete cycle,
$\text{v}_\text{mean}=\frac{\int_{0}^{2\pi}\omega\text{a}\cos\theta\text{d}\theta}{2\pi}=\frac{\omega\text{a}[\sin\theta]^2_0}{2\pi}=0$
So, $\text{v}_\text{mean}\neq\frac{2}{\pi}\text{v}_\text{max}$
Root mean square speed,
$\text{v}_\text{ms}=\sqrt{\frac{\text{v}^2_\text{min}+\text{v}^2_\text{max}}{2}}=\sqrt{\frac{0+\text{v}^2-\text{max}}{2}}$
$\text{v}_\text{ms}=\frac{1}{\sqrt{2}}\text{v}_\text{max}$