M5C3

Question 1

Define simple harmonic motion (S.H.M)

Answer 1

A body will oscillate with simple harmonic motion if it’s acceleration is directly proportional to its displacement from a fixed point and always directed towards that fixed point

Question 2

How do you calculate phase difference?

Answer 2

ɸ = 2πΔt/T 
ɸ = d/λ 2π
T = period (s)
f = frequency (Hz)
ɸ = phase difference (rad)
d = distance between two points

Question 3

What are the equations for angular velocity?

Answer 3

ω = 2πf 
ω = 2π/T
T = period (s)
f = frequency (Hz)
ω = angular frequency (rad s-1)

Question 4

Define amplitude

Answer 4

The distance in meters from the center of rotation

Question 5

Define phase difference

Answer 5

The fraction of a complete cycle or oscillation between two oscillating points

Question 6

What is the equation for displacement when starting at maximum displacement and the minimum displacement?

Answer 6

x = Acosωt (maximum)
x = Asinωt (minimum)
x = displacement (m)
A = maximum displacement (m)
ω = angular frequency (rad s-1)
t = time (s)

Question 7

What is the equation for velocity when starting at maximum displacement and the minimum velocity?

Answer 7

x = -ωAcosωt (maximum)
x = -ωAsinωt (minimum)
x = velocity (m s^-1)
A = maximum displacement (m)
ω = angular frequency (rad s-1)
 t = time (s)

Question 8

Define isochronous

Answer 8

Constant and independent to the amplitude of any oscillation (occurring at the same time)

Question 9

Define isochronous

Answer 9

Constant and independent to the amplitude of any oscillation (occurring at the same time)

Question 10

What is the equation for frequency?

Answer 10

f = 1/T
f = frequency (Hz or s^-1)
T = time period (s)

Question 11

When a pendulum is moving with simple harmonic motion what is it’s total energy equal to?

Answer 11

Total energy = GPE + KE

As GPE falls KE rises and vice versa

Question 12

When a spring is moving with simple harmonic motion what is it’s total energy equal to?

Answer 12

Total energy = GPE + KE + EPE

Question 13

Define damping

Answer 13

Damping forces reduce the amplitude of an oscillation with time, due to the energy being removed from the oscillatory system

Question 14

When is damping considered natural damping

Answer 14

When the damping forces are caused by natural forces (e.g. friction and air resistance)

Question 15

What is artificial damping?

Answer 15

When damping forces are caused by artificial forces

Question 16

What’s natural damping?

Answer 16

Damping caused by natural forces (frictional forces) for example air resistance

Question 17

When is damping considered artificial?

Answer 17

When damping forces are caused by external or manmade factors an example of this is a shock absorber in a car

Question 18

Explain light damping

Answer 18

When the amplitude of the oscillation decays slowly with time (exponential decaying to zero) due to the energy removed from the oscillatory system

Question 19

Explain heavy damping

Answer 19

When the amplitude of the oscillation decays and the time period of the oscillation slightly increases each cycle

Question 20

state what is meant by very heavy damping

Answer 20

No oscillation occurs and the body slowly moves back equilibrium

Question 21

What is resonance?

Answer 21

When the driving frequency is equal to the natural frequency of the system that’s oscillating. Results in the body oscillating at its natural frequency with maximum amplitude.

Question 22

Define free oscillation

Answer 22

Occurs when there is no external periodic force present. The system is oscillating at its natural frequency

Question 23

Define natural frequency

Answer 23

The frequency a body will oscillate at when it’s undergoing free oscillation

Question 24

What is forced oscillation?

Answer 24

When an external force, driving force, is applied to a body to keep the body oscillating. The system oscillates at the frequency of the driving force

Question 25

What is meant by driving frequency?

Answer 25

The frequency at which the driving force oscillates.

Question 26

What happens in a forced oscillation?

Answer 26

With a system that is subject to forced oscillations there will always be at least 2 objects that are oscillating;
1st object – The object (driver object) causing the vibration. This objects frequency is called the ‘driving frequency’.
2nd object – This object (slave object) is being made to oscillate due to object 1’s oscillatory motion. Object 2 will have a ‘natural oscillatory frequency’.