WEEK 9 (Mechanical oscillation)

Question 1

What is Hook’s law and what does it show?

Answer 1

F = -kx

Restoring force always pushes or pulls the object towards the equilibrium position

Question 2

What is amplitude?

Answer 2

Maximum distance of the object from the equilibrium position

Question 3

What is period?

Answer 3

The time it takes object to move through one complete cycle of movement

Question 4

What is frequency?

Answer 4

The number of complete cycles or vibration per unit of time

Question 5

What is ‘Damped oscillation’?

Answer 5

We always have a force of FRICTION, it reduces energy of the object and movement becomes damped

Question 6

What is the difference between Harmonic movement and waves?

Answer 6

Harmonic movement = motion of mass
Waves = motion of disturbance

Question 7

What are the two types waves?

Answer 7

Transverse wave & Longitudinal wave

Question 8

Where are transverse waves found?

Answer 8

• solid objects
• liquid
• gas interface

Question 9

What happens when waves travel from one media to another?

Answer 9

• Amplitude, wavelength and velocity changes
• Frequency & Period doesn’t change

Question 10

What is the difference between ‘In phase’ and ‘Out of phase’

Answer 10

In phase - Constructive interference
Out of phase - Destructive interference

Question 11

What does the speed of sound in a fluid depend on?

Answer 11

The fluid’s compressibility and inertia

Question 12

Define Bulk modulus

Answer 12

The ratio of the change in pressure to the resulting fractional change in volume

Question 13

Speed of sound depends on _______________

Answer 13

Temperature

Question 14

The equation for sound including Young’s modulus is valid only for what?

Answer 14

A thin, solid rod

Question 15

What is the average intensity of a wave?

Answer 15

The average intensity I of a wave on a given surface is defined as the rate at which energy flows through the surface, ΔE/Δt, divided by the surface area A . The direction of energy flow is perpendicular to the surface at every point.

Question 16

What is the relative intensity of a sound called?

Answer 16

Intensity level/Decibel level

Question 17

The loudest tolerable sounds have intensities about _________________ times greater than
 the faintest detectable sounds.

Answer 17

1.0 x 1012

Question 18

Where does Decibel come from?

Answer 18

Decibel comes from Alexander Graham Bell
(1847–1922), inventor of telephone

Question 19

Describe an application of the Doppler effect

Answer 19

It is possible to measure the speed of the blood flow in the body with a device called an ultrasonic flow meter, which makes use of the Doppler effect. The flow speed is found by comparing the frequency of the waves scattered by the flowing blood with the incident frequency

Question 20

What is louder, long wavelength & low frequency or small wavelength & high frequency?

Answer 20

Small wavelength & High frequency

Question 21

When do vibration amplitude reach their maximum?

Answer 21

Its amplitude reaches a maximum when the frequency of the driving force equals the natural frequency of the system f0, called the resonant frequency of the system. Under this condition, the system is said to be in resonance 


Question 22

What are three basic tasks of the auditory system (ear):

Answer 22

• deliver acoustic stimulus to the receptors
• transduce the stimulus from pressure to electric signals
• process electric signals to indicate pitch, loudness and location