4. Simple Harmonic Motion

Question 1

Define “cycle”

Answer 1

Cycle = one cycle is defined as one complete osciallation of the pendulum. In circular motion; one cycle is one complete circle or 2 π radians.

Question 2

Define “Time period (T)”

Answer 2

Time period (T) = The time period taken for one complete cycle

Question 3

Define “Equilibrium position”

Answer 3

Equilibrium position = The position where the pendulum bob would rest if not disturbed - position O

Question 4

Define “Amplitude”

Answer 4

Amplitude (X_o) = Defined as the maximum displacement from the equilibrium position, distance OA or OB (unit meter)

Question 5

Define “Frequency (f)”

Answer 5

Frequency (f) = The number of cycles that the pendulum makes per unit time. 1 / time period. Unit s^-1 or Hz

Question 6

Define “Angular frequency (w)”

Answer 6

Angular frequency (w) = is found by multiplying f by 2π (w = 2πf). This quantity is normally used when describing circular motion. An angular frequency of 2π rads s^-1 means that a body makes one revolution per second.

However, it is also used to describe an oscillation, 2π being equivalent to one complete cycle. Unit: s^-1 or herts (Hz)

Question 7

Give two examples of oscillations and a description of each

Answer 7

• The pendulum:
  
  • A bob that is swinging
  • When the bob is at the lowest position, it is travelling at its maximum speed.
  • No matter where the bob is, its acceleration is always directed towards O.
• Mass on a spring
  
  • Forces acting on; weight and tension.
  • Short spring = Small tension
  • Long spring = Large tension

Question 8

What is meant by Simple Harmonic Motion?

Answer 8

SHM = The acceleration is proportional to the distance from a fixed point. The accleration is always directd towards a fixed point.