Equation cards Flashcards
Vectors - Resolving a force into its horizontal component?
Fx=Fcosθ
Vectors - Resolving a force into its vertical component?
Fy=Fsinθ
Suvat equation beginning with v?
v = u + at
Suvat equation beginning with s, and using v?
s = 1/2 ( u + v ) t
Suvat equation beginning with s, using a?
s = ut + 1/2 at^2
Suvat equation beginning with v^2?
v^2 = u^2 = 2as
Extra suvat equation, without u in it?
s = vt - 1/2 at^2
Rules for using suvat?
Constant acceleration, moving in a straight line
What do the symbols stand for in suvat?
s=displacement u=initial velocity v=final velocity a=acceleration t=time taken for the change in velocity
Equation for force?
force = mass x acceleration
Equation for weight?
weight = mass x gravity
Force equation using momentum?
force = change in momentum/change in time
Momentum equation?
momentum = mass x velocity
Power/energy efficiency equation?
useful output energy/total input energy ( x 100% )
What is the moment of a force?
moment = force x perpendicular distance of the line of action of force from the axis or point of rotation
What is the torque of a force?
torque = one of the forces x perpendicular separation between the forces
Density equation?
density = mass/volume
Pressure equation?
pressure = force/area
Pressure in liquids equation?
pressure = height of the liquid column x density of the liquid x gravity
Work done equation?
work done = force x distance moved in direction of the force
Work done equation using an angle?
work done = F x cos θ
Power equation?
Power = work done/ time taken
Power equation using speed?
Power = force x speed
Restoring force exerted by the spring on that end?
Force = the spring constant x the displacement of the springs end from its equilibrium position
Energy for springs using force?
Energy = 0.5 x force applied x the extension
Energy for springs using the spring constant?
Energy = 0.5 x spring constant x extension^2
Stress equation?
Force load/area
Strain?
extension/length
Young modulus?
stress/strain
Charge?
Change in charge = current x change in time
Current?
current = cross-sectional area x number density x charge of electrons x mean drift velocity
Work done?
work done = voltage x charge
therefore, WD = EMF x charge
Work done, representing Q in a different form?
WD = V x I x t
Resistance equation, involving resistivity?
Resistance = resistivity x length / area
Resistance in series?
R = R1 + R2 …
Resistance in parallel?
1/R = 1/R1 + 1/R2 …
Power equation, with v?
Power = voltage x current
Power equation, with r?
Power = current^2 x resistance
Power equation, with both v and r?
Power = voltage^2 / resistance
Equation for internal resistance, without v?
EMF = current x ( resistance x internal resistance)
therefore,
EMF = voltage + (current x internal resistance)
Voltage equation, simple form?
Voltage = current x resistance
What actually is EMF?
The potential difference across a cell, when delivering no current
Definition of EMF?
Electromotive force = the energy transferred from some other form into electrical energy per unit charge
