A-level Mechanics OCR G484 Flashcards Preview

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Flashcards in A-level Mechanics OCR G484 Deck (59)
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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

Equatorial orbit
Same period as Earth (fixed point above the Earth’s surface)


Define displacement

Is the distance of a body from the equilibrium position and is directed from the start to end point


Define amplitude

The maximum displacement


Define period

Time taken to compete one oscillation/cycle


Define frequency

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.
Elastic collisions
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.