Define Linear momentum
the product of mass and velocity
Define net force on a body
equal to the rate of change of momentum
Define impulse of a force
Area under a force/time graph.
Change in momentum
Define a perfectly elastic collision
A collision which results in no change/loss of kinetic energy
Define an inelastic collision
Total energy is conserved though some loss of kinetic energy (during collision). The magnitude of the impulse on each object is the same.
Define the radian
The angle where the arc of a circle equals the radius
Define gravitational field strength
Force per unit mass (at a point in a gravitational field)
Define the period of an object describing a circle
The time taken for the object to describe a complete circle/orbit
Define a geostationary orbit of a satellite
Same period as Earth (fixed point above the Earth’s surface)
Is the distance of a body from the equilibrium position and is directed from the start to end point
The maximum displacement
Time taken to compete one oscillation/cycle
Number of oscillations/cycles per unit time
Define angular frequency
Product of 2π x frequency or 2π/period
Define phase difference
The angle, in radians between subsequent wave peaks
Define simple harmonic motion
Force/acceleration is (directly) proportional to displacement (from the equilibrium position) and is directed towards the equilibrium position.
Define pressure of a gas
Collisions with surface of large numbers of particles travelling randomly exerts a force (or each collision has a change of momentum)
Pressure = Force / Area
Define internal energy
The sum of the random distribution of kinetic and potential energies associated with the molecules of a system
Define specific heat capacity
The amount of thermal energy required to raise 1kg of substance through one degree Kelvin.
Define the newton
The force which gives a mass of 1kg an acceleration of 1 ms-2
Define the Kilowatt-hour
1kWh is the energy used/provided by a 1 kW device in 1 hour
State the uses of geostationary satellites
State Newton's three laws of motion
1st: A body will remain at rest or continue to move with constant velocity unless acted upon by a force
2nd: Force is proportional to rate of change of momentum
3rd: When one body exerts a force upon another, the other body exerts an equal but opposite force on the first body.
State the principle of conservation of momentum
(linear momentum) Total momentum is conserved.
For a closed system / no external forces
State Newton’s law of gravitation
The attraction of two masses is directly proportional to the product of their mass and inversely proportional to the square of their distance apart/separation
State Boyle’s law
Pressure is inversely proportional to volume for a fixed mass of gas at a constant temperature
State the effect of temperature on total internal energy
As temperature decreases, so does total internal energy; absolute zero is the temperature at which a substance has minimum internal energy.
State the basic assumptions of the kinetic theory of gases;
Volume of particles negligible compared to volume of container OR molecules much smaller than distance between them.
No intermolecular forces (except during collision) OR molecules only have kinetic energy.
Particles travel at a constant, rapid velocity (in straight lines) between collisions OR effect of gravity is small
Time of collision is much smaller than time between collision.
Gas consists of a large number of molecules moving randomly
State what is meant by a "mole"
One mole of any substance contains 6.02 × 1023 particles and that 6.02 × 1023 mol-1 is the Avogadro constant NA
Explain that F = ma is a special case of Newton’s Second Law
When the mass is constant, the rate of change of momentum ([change in mass] x [change in velocity] / time) can be expressed as mass x acceleration.