Periodic Motion

Question 1

What is centripetal acceleration?

Answer 1

The acceleration of an object in circular motion that acts towards the centre of an objects rotation

Question 2

What is centripetal force?

Answer 2

The resultant force responsible for an object in circular motion. It acts towards the centre of the objects rotation

Question 3

Definition of angular velocity

Answer 3

The angle through which an object moves through per unit time

Question 4

Angular velocity equation

Answer 4

ω = 2π/ T

Question 5

Definition of angular frequency

Answer 5

The angle through which an object moves through multiplied by frequency

Question 6

Angular frequency equation

Answer 6

ω = 2πf

Question 7

What is a radian?

Answer 7

The angle subtended at the centre of a circle by an arc equal in length to the radius

Question 8

How much is 2π in degrees

Answer 8

360

Question 9

Linear speed

Answer 9

Distance per unit time

v = ωr

Question 10

How can object move at a constant speed when moving in a circle but still be accelerating?

Answer 10

The velocity is changing, since the direction is changing but the magnitude of the products of velocity is constant. The centripetal acceleration is towards the centre of the circle

Question 11

How is linear acceleration related to angular velocity?

Answer 11

a = v²/r and a=ω²r

Question 12

What are the equations for centripetal force?

Answer 12

F = mv²/r and F = mrω²

Question 13

What causes an object to have centripetal force towards the centre?

Answer 13

Tension in string, gravity, electrostatic force of attraction, friction and magnetic force

Question 14

What is sinθ ÷ cosθ?

Answer 14

Tanθ

Question 15

If two waves are out of phase by T/4 what is the phase difference?

Answer 15

π/2

Question 16

If two waves are out of phase by T what is the phase difference

Answer 16

2π

Question 17

What equation links velocity and height?

Answer 17

v = √2gh

Question 18

What are the conditions for simple harmonic motion?

Answer 18

An objects acceleration is directly proportional to displacement and is in the opposite direction

Question 19

For SHM what is the maximum elastic potential energy?

Answer 19

Ep = 1/2kA2 where k is the spring constant and A is max amplitude

Question 20

SHM max kinetic energy

Answer 20

Ep = 1/2kA2 where k is the spring constant and A is max amplitude or 1⁄2 mω2A2

Question 21

What is damping?

Answer 21

An effect where the energy of an oscillating object is transferred to the surroundings decreasing the amplitude of the oscillations

Question 22

What is light damping?

Answer 22

The object continues to oscillate but the amplitude is decreased with time

Question 23

What is critical damping?

Answer 23

The object returns to the equilibrium position in the least possible time

Question 24

What is heavy damping?

Answer 24

The object does not oscillate and takes a long time to return to the equilibrium position

Question 25

What determines the frequency of oscillations of a loaded spring?

Answer 25

The frequency can be reduced by adding more mass/inertia or using weaker springs

Question 26

Energy in SHM

Answer 26

At equilibrium kinetic energy is maximum and potential energy is minimum.
At max amplitude kinetic energy is minimum and potential energy is maximum

Question 27

What are free vibrations

Answer 27

Oscillations where the total energy remains constant. No external force acts on the system and it vibrates at its natural frequency

Question 28

What is resonance

Answer 28

A case where the driver frequency is equal to the natural frequency of a system causing the amplitude of the oscillations to dramatically increase due to an additional gain of energy

Question 29

What is resonance frequency

Answer 29

When a system vibrates at the maximum amplitude. The increase in amplitude is due to a transfer of energy from the driving frequency

Question 30

What does the equation

x = Acosωt show

Answer 30

The A represents the amplitude and ω = 2π/T