formulas and units Flashcards
state hookes law
force= constant * extension
F=Kx
formula for moment
force * distance from pivot (at 90degrees)
F1d1 = F2d2
F1d1 + F2d2 = F3d3
pythagoras
aˆ2 = bˆ2+ cˆ2
force
mass x acceleration
mass=kg, a =m/s2
weight
mass * gravity
gravity= 9.8m/sˆ2
momentum
mass x velocity
impulse
= Force x contact time = change in momentum
velocity/speed
distance/time
acceleration
change in velocity / change in time
density
mass/volume
pressure laws in gas
1/volume
p1v1=p2v2
work
Force x distance (parallel to Force)
potential energy
mass x gravity x height
kinetic energy
= ½ x mass x (velocity)2
power. 4
work done/time taken
current * voltage
current ˆ2 * resistence
voltage ^2/ resistence
pressure
force/ area
pressure in liquids
= density x gravity x depth
current
charge/ time
potential difference (voltage)
work done/ charge
e.m.f
work done/ charge
ohms law
voltage= current * resistence
resistance
voltage/current
energy
voltage * current * time
resistence laws
bigger the length of wire, bigger the resistence
bigger the diameter of wire smaller the resistence
resistence in series
r= r1 +r2