Circular Motion and Oscillations

• How many radians are there is 360 degrees?

  2 pi
• What are the SI units of angular velocity?

  Radians per second.
• What is the definition of angular velocity?

  The rate of change of angle.
• How do you calculate angular velocity from time period (T)?

  Angular velocity = 2 pi / T
• How do you calculate angular velocity from frequency (f)?


  Angular velocity = 2 pi f
• What is required for uniform circular motion?

  A force that always acts perpendicular to velocity.
• Why doesn't a centripetal force do any work on an object in circular motion!

  The force has no component in the dircetion of motion/is always perpendicular to motion.
• How do you calculate linear velocity from the time period (T) of an object in circular motion?


  v = 2 pi r / T
• How do you calculate linear velocity from angular velocity?

  v = angular velocity x radius
• How is it possible for an object to experience an acceleration but travel at a constant speed?

  If acceleration is perpendicular to velocity, the velocity will change direction whilst speed is constant.
• What provides the centripetal force for a car turning a corner?

  Friction from the road on the tyres.
• What provides the centripetal force on the moon?

  The gravitational attraction of the Earth.
• Apart from friction what contributes to the centripetal force on a banked track?

  The horizontal component of the normal reaction.
• If a mass on a string is swung in a vertical circle where is the tension greatest?

  At the bottom of the circle.
• If a mass on a string is swung in a vertical circle where is the tension least?

  At the top of the circle.
• What is the equilibrium position in an oscillation?

  The point at which an object experiences no resultant force and thus no acceleration (the 'rest' position of an object).
• How many radians of phase are there in one complete oscillation?

  2 x pi
• How do you calculate the angular frequency of an oscillation?

  2 x pi x the frequency of the oscillation
• What are the conditions required for SHM?

  The acceleration of an object is proportional, to its displacement from equilibrium and always in the opposite direction.
• What is the acceleration of an object undergoing SHM when it's displacement is zero?

  Zero
• What is an Isochronous oscillator?

  An oscillator with a period/frequency that is not dependent on amplitude.
• What is a fiducial marker?

  A pin or pointer placed at the equilibrium position of an oscillation.
• What measures can be taken to improve the accuracy when measuring the time period of SHM?

  Time over multiple oscillations and calculate the average of several repeats.
• What is the kinetic energy of an SHM oscillator at maximum displacement?

  Zero
• How does the total energy in an SHM oscillator vary with time?

  It is constant.
• At what displacement is the potential energy of an SHM oscillator at a maximum?


  At maximum displacement (x=±A).
• How do you calculate the total energy of an SHM oscillator from its amplitude?

  E = ½ k A²
• What is a free oscillation?

  An oscillation in which no external driving force is present
• What causes damping of an oscillation?

  An external force opposing motion.
• What effect does damping of an oscillation have in terms of energy?

  It transfers the KE of the oscillation to other forms, usually thermal energy.
• What is light damping of an oscillation?

  A small damping force causing the amplitude of the oscillations to decrease slowly.
• What is heavy damping of an oscillation?

  A damping force that results in a rapid decrease in the amplitude of oscillations.
• What is very heavy damping of an oscillation?

  A large damping force that prevents any oscillations of the system when its displaced.
• What is the natural frequency of an oscillator?

  The frequency at which osicllation will occur in a system with no external driving forces (free oscillations)
• What is a forced oscillation?

  An oscillation in which a (periodic) external driving force is present
• What is a driving frequency in oscillations?

  The frequency of the external driving force in a forced oscillation
• What is resonance?


  When the driving frequency of a forced oscillation is close to the natural frequency of the system resulting in large amplitude oscillations.
• What is likely to occur when a mechanical system with little or no damping resonates?

  The amplitude of the oscillations will increase until the object breaks.
• What occurs in terms of energy during resonance?

  There is the greatest possible transfer of energy from the driver to the forced oscillation.
• What effects does increasing damping have on resonance?

  It reduces the maximum amplitude and it reduces the frequency of maximum amplitude.