PH4 syllbus definitions
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PH4 syllbus definitions
PH4 physics definitions
definitions of PH4 that i actually need
What is angular velocity?
angle swept out time taken
When acceleration is proportional to displacement from a fixed point and directed towards it.
What are free/natural oscillations?
When a system (with a mass and a force pulling it back to equilibrium) is displaced from equilibrium and released.
What are forced oscillations?
When a system capable of natural oscillations is subjected to a periodically varying driving force.
If in forced vibrations, the frequency of the applied force is equal to the natural frequency of the system. The amplitude of resulting oscillations is large.
What is critical damping? (don't need to memorise)
When the resistive forces on the system is just enough to prevent oscillations from occurring at all when the system is displaced and released.
Mass x velocity
State the principle of conservation of momentum
The vector sum of the momenta of bodies in a system stays constant provided there is no external resultant force.
What is an elastic collision?
A collision in which there is no change in total kinetic energy.
What is an inelastic collision?
A collision in which kinetic energy is lost.
What is Boyles law?
For a fixed mass of gas at constant temperature, the pressure varies inversely as the volume.
What is the Avagadro constant?
The number of particles per mole.
What is the internal energy of a system (U)?
This is the sum of the kinetic and potential energies of the particles of the system.
Define the first law of thermodynamics
Q = ΔU + W
Define electric field strength E and give units.
The force experienced per unit charge by a small positive charge placed in a field. Units = V m-¹ or N C-¹
Define gravitational field g and give units
The force experienced per unit mass by a mass placed in the field. Unit = ms-² or N kg-¹
Define electric potential with units
Elec Pot at a point = work done per unit charge in bringing a positive charge from infinity to that point.
Unit = V or (J/C)
Define gravitational potential with units.
Grav pot at a point = work done per unit mass in bringing a mass from infinity to that point
Give all three of Kepler's laws of planetary motion.
1. Each planet moves in an ellipse with the sun at one focus.
2. The line joining a planet to the centre of the star sweeps equal areas in equal times.
3. T^2 is proportional to r^3
Explain what is meant by centripetal acceleration
A body moving in a circular motion experiences an acceleration towards the centre of the circle