equations Flashcards
Describe Work done and it’s equation
Work done = energy transferred
Work done = force X distance moved
W = f X d
( can be E or W)
Describe power and it’s equation
Power is the rate of doing work
Power is on watts or j/s
Power = work done
____________
time
P = E or w / t
Describe kinetic energy and it’s equation
Energy of movement
Ke = 1/2 X mass X speed^2
Ke = 1/2 X m X v^2
Kinetic energy = joules
Describe Gpe and it’s equation
GPE is energy due to height and is measured in joules
KE gained = Gpe lost
GPE = mass X g X height
Equation for efficiency
Efficiency is measured in joules
Efficiency = (useful energy transferred divided by energy supplied) X 100
Energy output X 100
________________
Energy input
Equation for weight
W = mass X g (10) (moon 1.6)
W= m X g
Weight = newtons
G = n/kg
Equation for force
Force = mass X acceleration
F= ma
A = F / m
F = newtons A = m/s^2
Equation to work out speed or acceleration on a graph
= gradient = vertical
_________
Horizontal
To work out area on a graph
= distance travelled = speed X time
Equation for speed
Speed = distance / time
D = s X t
Equation for acceleration
Acceleration = v( final speed) - u
__________________
Time
Equation for power in electricity
P = w / t
W = ITV
V= VoLTs
W= joules
P = watts I = amps
Calculating current
Current = charge / time
I = Q / t
Q = coulombs
Calculating voltage
Voltage = elec energy converted/ charge
V = w( joules) / Q
Calculating resistance
Resistance = voltage / current
R = V/ I
R = ohms
