AP Physics C: Mechanics / Unit 7: Oscillations
7.4 Energy of Simple Harmonic Oscillators
Notes
Total energy $\displaystyle E=\frac{1}{2}kA^2$ stays constant (no friction). It switches between kinetic and potential.
- At the ends: all potential. At equilibrium: all kinetic.
Practice
$k=100$ N/m, $A=0.1$ m. Total energy:
$\displaystyle \frac{1}{2}(100)(0.01)$.
Doubling amplitude makes total energy:
$A^2$.
At equilibrium, the spring's potential energy is:
$x=0$.
Maximum speed of a spring oscillator with $k$, $m$, $A$:
$\displaystyle \frac{1}{2}kA^2=\frac{1}{2}mv^2$.
Ready for more? Take the Unit 7 test.