6.0 Further Mechanics And Thermal Physics Flashcards
Define angular speed
The rate of change of angular displacement
Implications of circular motion
an acceleration present that requires a centripetal force
What is angular speed measured in
Radians per second
What is centripetal acceleration
Acceleration acting towards the centre of rotation, causing the object to rotate
What is centripetal force
Force acting towards the centre of rotation, causing the object to rotate
Define simple harmonic motion (SHM)
A type of periodic motion where the acceleration of the object is directly proportional to its displacement. In opposing directions
What are the conditions for SHM
The force is proportional to the displacement and directed towards the equilibrium position
What are the characteristics of SHM
The motion is periodic, oscillating about the equilibrium position and the restoring force is from factors like gravity, or tension
How does kinetic energy vary in SHM
It is maximum at the equilibrium position and minimum at maximum displacement
How does potential energy vary in SHM
It is maximum at the maximum displacement and minimum at equilibrium position
Variation between total energy in SHM
Total energy remains constant, varying between Ke and Pe
Examples of simple harmonic systems
Mass-Spring systems, Simple pendulums, Tuning forks, vibrating molecules in solids
What is damping in oscillations
Damping is the effect of a resistive force that reduces the energy of a system, causing the amplitude to decrease
What are the three types of damping
Underdamping, critical damping, overdamping
Process of underdamping
The system oscillates with decreasing amplitude. Oscillations take time to stop
Process of critical damping
The system returns to equilibrium in the shortest possible time without oscillating
Process of overdamping
The system returns to equilibrium without oscillating, but more slowly than in critical damping
Effect of underdamping on period and frequency
the period increases slightly , but the frequency decreases.
Effect of critical and overdamping on period and frequency
These systems don’t oscillate so there is no period or frequency
What are free vibrations
They occur when the object oscillates without external forces after the initial displacement. Vibrating at its natural frequency
What is the natural frequency of an object
The frequency at which a system oscillates when displaced and released without external forces acting
What is a forced vibration
They occur when an external force is applied periodically, causing vibrations at the frequency of the applied force
What occurs when the applied frequency is equal to the natural frequency
Resonance occurs, resulting in a large increase in the amplitude of the oscillations
What is resonance
when the frequency of the applied force matches the system’s natural frequency, the system oscillates with a large amplitude
effects of light damping on resonance
Produces a sharp resonance peak with large amplitude
effects of overdamping on resonance
Reduces the amplitude and broadens the resonance peak
Define internal energy
The sum of the randomly distributed kinetic energies and potential energies of the particles in a body
Increase of internal energy
When energy is transferred by heating of having work done on it
Energies during changes of state
Potential energies change but kinetic energies do not
What is continuous flow
When a substance flows steadily and is continuously heated or cooled
Equation of continuous flow calculations
Q=(m-dot)(c)(delta-T)
symbol for specific heat capacity
c
symbol for specific latent heat
l
What are the three main gas laws
Boyle’s law, Charles’ law, Pressure law
Define Boyle’s law
Pressure is inversely proportional to volume for a fixed temperature and mass
Define Charles’ law
Volume is proportional to temperature for a fixed pressure and mass
Define the Pressure law
Pressure is proportional to temperature for a fixed volume and mass
What is the combined gas law
(p1V1)/T1=(p2V2)/T2
What is n in the first ideal gas equation
The number of moles
What is N in the second ideal gas equation
The number of molecules
Define absolute zero
The lowest possible temperature, where a system has minimum internal energy
The behavior of particles at absolute zero
They have no kinetic energy and motion theoretically ceases
What is molar mass
The mass of one mole of a substance
What is molecular mass
The mass of one molecule of a substance
calculating moles
number of moles=mass/molar mass
Define Brownian motion
The random, erratic movement of particles
How does Brownian motion provide evidence for the existence of atoms
the motion is caused by collisions with atoms or molecules surrounding it
What is the simple molecular model of gases
Gases are made up of tiny particles in Brownian motion. these move in straight lines until they collide with others or the walls of the container. the collisions are elastic, and there are no intermolecular forces
How does the model explain pressure
It is caused by the collisions of gas molecules on the walls of the container
How does the model explain volume
when the volume changes, the particles have more space and thus, lowers the pressure
How does the model explain temperature
Temperature is related to average kinetic energy, the faster the molecules move, the higher the temperature
problems between gas laws and the kinetic theory model
the gas laws are derived from observations and the kinetic theory model is just theory
Assumptions of the kinetic theory
- Particles only have kinetic energy
- All particles are identical
- Volume is negligible
- All collisions are elastic
- Particles follow Newtonian physics
- There are enough particles to be statistically significant
Steps in deriving the kinetic theory
- Pressure on walls of container cause change in momentum
- ## Particle rebounds with opposing velocity so momentum = 2mv
Internal energy of an idea gas
The kinetic energy of the atoms
Change of our understanding of thermal physics over time
through experimental evidence and discoveries, our understanding has built, giving us kinetic theory and gas laws
Define sensible heat
The energy required to heat up a substance without changing its state
