Oscillations

Question 1

What is simple harmonic motion

Answer 1

Oscillating motion for which acceleration is directly proportional to displacement and acts in the opposite direction of displacement. Gradient of graph of acceleration against displacement is -W^2

Question 2

What is an Isochronous Oscillator.

Answer 2

Time period T of oscillator is unaffected by amplitude. Amplitude is directly proportional to speed, so period remains unchanged.

Question 3

Graphs of energy against displacement

Answer 3

Total energy remains constant in SHM without friction. Simple pendulum: energy interchanges between potential and kinetic as it oscillates. At amplitude, all energy is potential. In equilibrium, no potential, maximum kinetic. Mass-spring system: potential energy from gravity and spring. Vertical: gravitational and elastic potential. Horizontal: only elastic potential. Potential energy is always positive.

Question 4

Equation for kinetic energy of a spring mass system

Answer 4

0.5 * Force constant of spring * (amplitude squared - displacement squared) - 1/2K(A^2-x^2)

Question 5

What is damping

Answer 5

Damping is when an external force acts on an oscillator and reduces the amplitude of its oscillations. Heavy damping is when the oscillatory movement is stopped.

Question 6

What is free oscillation

Answer 6

When a mechanical system is displaced from its equilibrium position and left to oscillate without any external forces. The frequency of the systems free oscillations is its natural frequency.

Question 7

What is forced oscillation

Answer 7

When a periodic driver force applied to oscillator, object vibrates at driving frequency. Example: Mass on spring, hand moves up and down, motion forces oscillation at the same frequency.

Question 8

What is exponential decay of a oscillator

Answer 8

When the amplitude of a damped oscillator decreases by the same factor in equal time intervals.