Equations Flashcards
Equation for moment
Moment,M ( newton metres,Nm) = Force,F (newtons,N) x perpendicular distance from line of action
Density
Density,p (kg/m3) = mass,m (kg) / volume,V (m3)
Specific latent heat of fusion, L⬇️F
This is solid to liquid
Specific latent heat of fusion,L⬇️F (J/Kg) = Energy,E (Joules,J) / Mass,m (Kg)
Specific latent heat of vaporisation, L⬇️V
This is liquid to vapour
Specific latent heat pf vaporisation,L⬇️V = Energy,E (Joules,J) / Mass,m (Kg)
Boyle’s Law
Pressure,p (Pressure,Pa) x Volume,v (Metres cubed,m^3) = Constant
Power (includes E and t)
Power,p (Watts,W) = Energy,E (Joules,J) / Time,t (seconds,s)
Power supplied to a resistor (includes I and R)
Power,P (Watts,W) = Current^2,I^2 (Amperes,A) x Resistance,R (Ohms)
Power Supplied
Power supplied, P (Watts,W) = Current,I (Amperes,A) x Potential difference,V (Volts,V)
Charge flow,Q
Charge flow,Q (Coulombs,C) = Current,I (Amperes,I) x Time,t (Seconds,s)
Energy transferred from the mains,E
Energy transferred from the mains, E (Joules,J) = Power,P (Watts,W) x Time,t (Seconds,s)
Efficiency (in terms of output and input)
Efficiency = (output power/energy. / .input power/energy) x 100
Current (includes V and R)
Current,I (Amperes,A) = Potential difference,V (Volts,V) / Component resistance,R (Ohms)
Total Resistance
Total Resistance,R⬇️total (Ohms) = R1 + R2
Potential difference across a component
Potential difference across a component,V (Volts,V) = Energy transferred,E (Joules,J) / Charge,Q (Coulombs,C)
Charge
Charge = current x time taken
