Formulae

• Power (P) = voltage x current
• Electric potential difference (V) = charge transfer / current
• Resistance (R) = voltage / current
• Resistance (R) = potential difference / current
• Ohm's law states that the current through a conductor between two points is directly proportional to the potential difference across the two points.
• The equation for Ohm's Law is V=IR, where V is the potential difference, R is the resistance, and I is the current.
• Current (I) = charge / time
• Charge (Q) = current x time
• A series circuit has only one pathway for electricity to flow through all components connected together.
• In an electrical circuit with multiple resistors connected in series, the total resistance can be calculated using the formula Rtotal = R1 + R2 + ...
• Power (P) = energy transferred per second
• State the formula for weight

  Weight = mass x gravity (w=mg)
• State the formula for work done


  work done = force x distance
• State the formula for calculating force


  force = spring constant x extension (f=ke)
• State the formula for calulating the distance travelled


  distance travelled = speed x time (s=vt)
• State the formula for calculating the period in a wave

  period = 1/frequency (T=1/f)
• State the formula for calculating wave speed

  wave speed = frequency x wavelength (v=fwavelenght)
• State the formula for efficiency in the terms of useful energy transferred

  efficiency = useful output energy transfer/total input energy transfer
• State the formula for efficiency in terms of power

  efficiency = useful power input/total power input
• State the formula for charge flow

  Charge flow = current x time (Q=IT)
• State the formula for potential difference

  Potential different = current x resistance (V=IR)
• State the formula for kinetic energy

  kinetic energy = 1/2 x mass x speed^2 (EK=1/2MV^2)
• State the formula for calculating elastic potential energy

  Elastic potential energy = 1/2 x spring constant x extension ^2 (epe= 1/2ke^2)
• State the formula for calculating gravitational potential energy


  REMEMBER THREE WORDS, MULTIPLY THREE THINGS

  gravitational potential energy = mass x gravity x height

  ep = mgh
• State the formula for calculating energy transferred in the terms of power

  energy transferred = power x time (E=PT)
• State the formula for calculating energy transferred in terms of charge flow

  Energy trasnferred = charge flow x potential difference (E=QV)
• State the formula for calculating power in the terms of energy transferred

  power = energy transferred / time (P=E/T)
• State the formula for calculating power in the terms of work done

  power = work done/time (P=W/T)
• State the formula for calculating power in the terms of potential difference

  power = potential difference x current (P=VI)
• State the formula for calculating power in the terms of current

  power = current^2 x resistance (P=I^2R)
• What is the formula for calculating the gradient on a distance/time graph and what should you use if asked to calculate displacement using vectors?

  Gradient = distance travelled/time taken

  -use Pythagoras to calculate the hypotenuse as that it the displacement
• What is the formula to calculate acceleration (given you are told the time)

  Acceleration (m/s^2) = change in velocity (m/s) / time (s)
• What are the different ways SUVAT questions could be asked?


  'Calc final velocity' = v^2 = u^2 + 2as

  'Calc initial velocity' = u^2 = v^2 - 2as

  'Calc distance' = s = v^2 - u^2 /2a

  'Calc acceleration' = a = v^2 - u^2 /2s
• Define scalar and vector quantities and give examples


  Scalar quantities = quantities with magnitude but NOT direction

  Vector quantities = quantities with both magnitude AND direction

  Scalar - mass, temp, energy, speed

  Vector - force, acceleration, velocity