Oscillation: A back-and-forth or up-and-down motion occurring around a central point known as the equilibrium position.
Amplitude: The maximum displacement from the equilibrium position to the maximum distance traveled. Amplitude does not affect the time period.
Full Oscillation (Full Cycle): A complete motion starting from a specific point (usually an extreme), moving to the opposite side, and returning to the same starting point.
Time Period and Frequency Formulas
Time Period (T): The time taken for one complete oscillation.
Basic Equation: T=nt, where t is time and n is the number of oscillations.
Mass Spring System: Calculated as T=2πkm, where m is mass and k is the spring constant.
Simple Pendulum: Calculated as T=2πgL, where L is the length of the rope and g is gravity (9.8m/s2).
Frequency (f): The reciprocal of the time period, f=T1 or f=tn.
Angular Frequency (ω): Described as ω=T2π or ω=2π×f.
Kinematics Graphs of Oscillations
Displacement vs. Time: Produces a sine wave or sinusoidal graph as the object moves between positive and negative maximums.
Velocity vs. Time: Represented by a cosine graph.
- Maximum Velocity: Occurs when the object passes through the equilibrium position.
- Zero Velocity: Occurs at the extremes (maximum displacement) where the object momentarily stops.
Acceleration vs. Displacement: A straight line sloping downwards.
- When displacement is negative maximum, acceleration is positive.
- When displacement is positive maximum, acceleration is negative.
Questions & Discussion
Question: "Can you explain the velocity time graph one more time?"
Response: At the equilibrium point (t=0), velocity is at its maximum. As the oscillator reaches the maximum compression/extension point (extreme), it stops for a millisecond, resulting in zero velocity. On the return through the midline, velocity is maximum in the opposite direction.
Question: "In radians or… Because of the pi?"
Response: The context of the calculation (T=2πkm) isn't an angle, so the unit of the calculator doesn't change the result, though the formula uses radians components.
Question: "Is it hard?"
Response: The instructor noted the work on the pendulum calculation (T=2πgL) results in 0.17 for length when solving for a specific period.
Discussion on units: The unit for frequency is analyzed as Hz. A calculation result given was 1.2s for the time period and approximately 7.54 for angular frequency (ω).