10. Oscillations

Question 1

What is periodic movement?

Answer 1

any motion that repeats itself at equal time intervals

Question 2

What is an oscillatory movement?

Answer 2

a particle in oscillatory motion that moves back and forth over the same path

Question 3

What is equilibrium position?

Answer 3

equilibrium position is the position which no net force acts on an oscillating body

Question 4

What is amplitude?

Answer 4

amplitude of an oscillation is the maximum displacement of an oscillating body from equilibrium

Question 5

What is period?

Answer 5

period is the time taken to complete one oscillation

Question 6

What is frequency?

Answer 6

frequency is the number of complete oscillations completed per unit time. (f= 1/T)

Question 7

What is angular frequency?

Answer 7

angular frequency w is a constant of a given oscillator and is related to natural frequency by w=2∏f

Question 8

What is the net force at equilibrium position?

Answer 8

Fnet=0

Question 9

At what point does the mass move at maximum velocity?

Answer 9

equilibrium position

Question 10

At what point does the mass move with maximum acceleration?

Answer 10

at maximum displacement

Question 11

What is simple harmonic motion? (acceleration is?)

Answer 11

acceleration is
1. proportional to its displacement from eqm point
2. always directed towards the eqm point (opposite direction to displacement)

Question 12

What is the equation defining s.h.m?

Answer 12

a= -w²x

Question 13

Show s.h.m from N2L and Hooke’s law

Answer 13

F internal = -kx
F = ma
a = -w²x
equate together

Question 14

What is the relation of acceleration a and displacement x ?

Answer 14

acceleration is proportional to displacement

Question 15

what is heavy damping?

Answer 15

no real oscillation, system returns very slowly to the equilibrium position.

Question 16

What is resonance?

Answer 16

resonance occurs when the driving frequency equals to the natural frequency of a body, giving maximum amplitude of oscillation.

Question 17

What is the relation of the degree of damping and the amplitude?

Answer 17

As degree of damping increases, amplitude of vibration at all frequencies decrease

Question 18

What is the relation of the degree of damping and the resonant peak?

Answer 18

As degree of damping increases, the resonant peak becomes broader and occurs at lower frequencies

Question 19

What is critical damping?

Answer 19

the oscillator returns to the equilibrium position as quickly as possible, without oscillating

Question 20

What is light damping?

Answer 20

continuous oscillation of constant period but decreasing amplitude.