P1 - Periodic motion Flashcards
What is angular speed? what’s the symbol?
Angular speed is the angle an object rotates around per second.
w, omega
What is frequency?
what is period?
what’s the symbol for period?
The frequency f, is the number of complete revolutions per second ‘hertz’.
The period is the time taken for a complete revolution in seconds.
T
Why is there centripetal force when a object is moving in a circle?
What direction does the centripetal acceleration act?
Objects travelling in circles velocity is changing, Even if the object is going at constant speed, this is because its velocity is constantly changing as its direction is changing. As its velocity is changing there must be a force causing this (centripetal force)
Towards the centre of the circle
What is linear velocity?
What is the relationship between linear velocity and linear speed?
What is the magnitude of linear velocity?
How fast an object is moving in a straight line
linear velocity has the same magnitude as linear speed but is a vector that’s a tangent to the circle so same magnitude but different directions
Linear speed and the magnitude of linear velocity are the same thing
Why is there a centripetal force when an object moves in a circle?
Since an object travelling in a circle has a centripetal acceleration there must be a force causing thus acceleration. This is known as the centripetal force.
what is simple harmonic motion?
An oscillation in which the acceleration of an object is directly proportional to its displacement from its equilibrium position, and is directed towards the equilibrium.
When displacement is positive maximum what is the velocity and acceleration? (SHM)
velocity is 0 as its just about to swing back
acceleration is maximum negative as its negative distance away and all the energy is potential
when displacement is 0 what is velocity and acceleration? (SHM)
velocity is maximum negative or positive depending on which way it has swung as as much energy as possible is now kinetic
acceleration is 0
when displacement is negative 0 what is the velocity and accerlation? (SHM)
accerleration = 0
velocity is positive maximum
How does potential and kinetic energy affect each other as a object oscillates?
As potential energy is 0, kinetic energy is maximum, vise versa this is because ek + ep = total energy (mechanical energy). energy is transferred from one store to e=another through the oscillation
What does big A stand for in SHM equations?
when do we normal use this?
Amplitude in m^2 (maximum displacement)
when amplitude is maximum displacement
what is the period when dealing with SHM?
the time it takes for one complete oscillation so all the way left to all the way right back to the left position
What is free vibration’s?
example?
free vibrations involve no transfer of energy to or from the surroundings.
when you stretch a mass on a spring
what is forced vibrations?
what is driving frequency?
what happens when the driving frequency is much less than the natural frequency?
what happens when the driving frequency is much greater?
Forced vibrations happen when a system is forced to vibrate by a periodic external driving force.
The frequency of the external driving force
The two frequencies are in phase,
But if the driving frequency is much greater than the natural frequency the oscillator wont be able to keep up (in antiphase)
what is resonance?
what is the phase difference between the driver and the oscillator when resonating?
when the driving frequency approaches the natural frequency the system gains more and more energy from the driving force and so vibrates with a rapidly increasing amplitude till maximal amplitude osccilations. (resonating)
(90degrees)
