Simple Harmonic Motion

Question 1

What is simple harmonic motion?

Answer 1

a common type of oscillation where an object vibrates about an equilibrium position under the influence of an unbalanced force

Question 2

What must be true about the unbalanced force in simple harmonic motion?

Answer 2

• always directed towards the equilibrium position

* proportional to the displacement of the object from the equilibrium position

Question 3

What are the equations for simple harmonic motion?

Answer 3

• y=Awsinwt
• y=Awcoswt
• a=-w²y
• F=-kx

Question 4

What is the relationship between the spring extension and tension?

Answer 4

the spring extension is directly proportional to the tension in the spring

Question 5

How is the constant of proportionality represented?

Answer 5

k

Question 6

What is the opposing equal force to the stationary mass in equilibrium?

Answer 6

the resting force

Question 7

What can be said about spring constant and resting force?

Answer 7

they are equal

Question 8

What is the symbol for the spring constant?

Answer 8

k, it has the units Nm⁻¹

Question 9

What is the equation for Hooke’s law?

Answer 9

F=ky

Question 10

What is the amplitude?

Answer 10

the maximum displacement of an oscillating object from the zero displacement (equilibrium) position

Question 11

What is the frequency of the SHM?

Answer 11

the number of complete oscillations performed

Question 12

For an object to be performing simple harmonic motion what must the net force acting on it be proportional to?

Answer 12

displacement

Question 13

What quantity is continuously changing as an object oscillates?

Answer 13

acceleration

Question 14

What happens as the displacement of the mass increases?

Answer 14

the velocity decreases therefore the kinetic energy of the mass decreases

Question 15

What happens to the lost energy in SHM?

Answer 15

it is stored as potential energy in the spring

Question 16

What is the relationship between elongation and potential energy?

Answer 16

The more the spring is stretched or compressed the greater the potential energy stored in it

Question 17

What is the case when the kinetic energy is at a maximum?

Answer 17

when the speed of an oscillating object is at a maximum, this is when the displacement (y) =0

Question 18

What happens when y=a?

Answer 18

• the velocity is momentarily zero and so the kinetic energy is zero
• the restoring force acting on the object is at a maximum at this point and so the potential energy is at a maximum

Question 19

A mass attached to a spring is oscillating horizontally on a smooth surface. At what point in its motion does kinetic energy have a maximum value?

Answer 19

when the displacement from the rest position is zero

Question 20

What does A equal?

Answer 20

amplitude

Question 21

What is the equation for kinetic energy?

Answer 21

Ek=1/2mw^2(A^2-y^2)

Question 22

What is the equation for potential energy?

Answer 22

Ep=1/2mw^2y^2

Question 23

What happens as a SHM system vibrates?

Answer 23

energy is converted between potential (Ep) and kinetic (Ek)

Question 24

What can be said about the energy of waves?

Answer 24

The energy of the waves is directly proportional to the square of the amplitude

Question 25

What is the intensity/irradiance?

Answer 25

The amount of energy per second per unit area

Question 26

What is power?

Answer 26

The amount of energy per second

Question 27

What is the equation for intensity?

Answer 27

I=P/A

Question 28

What is intensity directly proportional to?

Answer 28

The square of the waves amplitude

Question 29

What does a phase difference of a whole number result in?

Answer 29

Perfectly constructive interference

Question 30

What is perfectly constructive interference?

Answer 30

Peak meets peak and trough meets trough

Question 31

What does a phase difference of n+1/2 result in?

Answer 31

Perfectly destructive interference

Question 32

What is perfectly destructive interference?

Answer 32

Peak meets trough and trough meets peak

Question 33

In perfectly destructive interference what is the amplitude?

Answer 33

The amplitude of the combined wave is 0m

Question 34

What is the amplitude of a perfectly constructive interference?

Answer 34

The amplitude of the combined wave is 2A

Question 35

What is damping?

Answer 35

When the amplitude of oscillation of a pendulum gradually decreases to zero due to air resistance

Question 36

What happens to the total energy of a system during damping?

Answer 36

The total energy of the pendulum will decrease to zero

Question 37

What happens to the amplitude during damping?

Answer 37

The amplitude decreases with each half-damped oscillation

Question 38

What is the phase difference?

Answer 38

A measure of the separation of these two points as a fraction of the wavelength and expressed as an angle in radians

Question 39

What happens if the amplitude of a wave doubles?

Answer 39

The intensity of the wave increases four times

Question 40

What are nodes?

Answer 40

Positions of zero disturbance in a stationary wave

Question 41

What does the distance between nodes equal?

Answer 41

Half a wavelength

Question 42

What are points of maximum disturbance called?

Answer 42

Antinodes

Question 43

What causes a stationary wave to form?

Answer 43

By the superposition (or overlapping) of the incident wave and the reflected wave

Question 44

When does an object not have a simple harmonic motion?

Answer 44

When the acceleration(a) or force(F) is directly proportional to the negative displacement from the equilibrium position. This can’t be described as SHM as the object has a constant speed.

Question 45

When does the maximum potential energy in SHM occur?

Answer 45

When y has a maximum value i.e y=A

Question 46

What can be said about Ek when Ep is at a maximum?

Answer 46

Ek is at a minimum

Question 47

What can be said about the energy of travelling waves?

Answer 47

It is directly proportional to the square of the amplitude

Question 48

Do you know the equation to calculate the phase difference?

Answer 48

2pix/wavelength

Question 49

What is the disturbance?

Answer 49

The height of the combined wave

Question 50

What are coherent waves?

Answer 50

Waves with the same path difference

Question 51

What does a phase difference of a whole number multiple of 2 π result in?

Answer 51

Perfectly constructive interference

Question 52

What does a phase difference of (n+1/2)x2 π result in?

Answer 52

Perfectly destructive interference

Question 53

What do we associate standing waves with?

Answer 53

Musical instruments

Question 54

What is the first harmonic often referred to?

Answer 54

The fundamental

Question 55

What does the wavelength of any node equal?

Answer 55

The distance between adjacent nodes x2

Question 56

What does the amplitude of oscillation depend on?

Answer 56

Particle position