pysics
- Created by: DodsonAleah
- Created on: 13-02-18 13:31
Work done (measured in joules) = force(in newtons) x Distance moved in the direction of force(meters)
Power (watts) work done (Joules) divided by time taken(seconds)
remember than there are so seconds in a minute a 60 seconds in an hour.
Effiency (as a percentage) = useful output energy divided by total input energy x 100(percent)
How to create a scale drawing:
1. choose a scale, e.g 1cm= 10 newtons
2.using a ruler, potractor and pencil draw the line to represent the force at the correct angle.
3.from this draw a right-angled triangle
4. measure the lengths and convert back to newtons.
MOMENTS
moment (measured in newton-meters, Nm) = force(n) x distance normal to the direction of force(m)
sum of the clockwise moments = sum of the ant-clockwise moments)
CIRCUIT COMPONENTS
batteries and cells provide voltage
switches allow current to be continued or discontinued, (switched on or off)
voltmeters measure voltage
ammeters measure current
a fixed resistor provides fixed resistance to current flow
a variable resistor provides changeable resistance
filament lamps convert electrical energy into useful light energy
motors convert electrical energy into useful kinetic energy
diodes allow current to flow in only one direction
thermistors, resistance decreases when temperature increases
ldr - resistance decreases when light intensity increases
led- a diode the produces light as current flows through it
SERIES + PARALELL CIRCUITS
ammeters must be connected in series, voltmeters must be connected in parallel because ammeters have low resistance and voltmeters have high resistance.
electrons do not flow through any of the voltmeters
the voltage across all components in a series circuit should add to make the voltage in the cell, battery or power pack.The current is the same at any point.
The voltage across the components in each branch of a paralell circuit should add to make the cell voltage the voltage readings from any resistor woll be the same as that of the cell, so long as they are in paralell. The sum of the current in each branch is equal to that which leaves the cell.
CURRENT AND CHARGE EQUATION
charge(coulombs) = current x time(seconds)
ENERGY AND CHARGE EQUATION
energy transferred(joules)= charge moved (coulombs)x voltage(volts)
OHM'S…
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