Forces Motion And Electricity Flashcards

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1
Q

Unit of speed and velocity

A

M/s

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2
Q

Speed is…

Velocity is…

A

Speed is how fast you are going

Velocity is the same but the direction is also specified

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3
Q

Acceleration =

A

Change in velocity/tine

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4
Q

What is acceleration

A

How quickly the velocity is changing

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5
Q

Distance time graphs

A
Gradient = speed
Steeper is faster 
Flat is where stopped 
Downhill is going back to starting point
Curves are accel or deccel
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6
Q

Velocity time graphs

A

Gradient = acceleration
Flat is steady speed
Steeper is greater accel or deccel
Curve is changing acceleration

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7
Q

Weight =

A

mass x gravitational field strength

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8
Q

Terminal velocity

A

A final speed you hit when falling, it is related to its weight and drag

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9
Q

First law of motion

A

Balanced forces mean no change in velocity

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10
Q

Second law of motion

A

If there is an unbalanced force than the object will accelerate in that direction
Another word for this is the resultant force

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11
Q

Third law of motion

A

Reaction forces

If you push on something it pushes back and the smallest mass is accelerated further

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12
Q

Resultant force =

F

A

Mass x acceleration

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13
Q

Stopping distance =

A

Whole time to stop

Braking distance + thinking distance

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14
Q

Thinking distance

And factors

A

Distance car travels for driver to react and apply brakes

Speed
Reaction time/state (tired or drunk)

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15
Q

Braking distance

And factors

A

The distance car travels during brakes on to stop

Speed
Mass of vehicle and people inside
State of brakes
Grip - road weather. Tyres.

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16
Q

Momentum =
(P)
Kg m/s

A

Mass x velocity

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17
Q

Momentum before =

A

Momentum after

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18
Q

Force =

A

Change in momentum/time taken for change to happen

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19
Q

Crumples zones

A

Crumple on impact to increase the time taken for a car to stop

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20
Q

Seat belts

A

Stretch slightly to increase the time taken for a wearer to stop
Reduce force on chest

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21
Q

Air bags

A

Also slow you down more gradually

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22
Q

A moment is a

A

Turning effect of a force

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23
Q

Moment (nm) =

A

Force (n) x perpendicular distance between line of action and pivot

24
Q

Centre of gravity

A

Directly below the point of suspension

25
Q

Force causing orbits

A

Gravity

26
Q

Gravity decreases as

A

You get further away

27
Q

Some orbits are

A

Elliptical (elongated)

28
Q

For a circular orbit the distance travelled is the

A

Circumference

29
Q

Orbital speed =

A

(2 x pi x orbital radius)/time

30
Q

Speed =

A

Distance/time

31
Q

plastic is an…

A

insulator

32
Q

the live wire

A

red wire

alternates between high voltage and low voltage of about 230V

33
Q

the neutral wire

A

blue
always at zero V
elect flows through live and out neutral

34
Q

earth wire

A

green/yellow (colorblind)
connected to power supply and is a back up wire
there in case fault with main wires
connected to the ground

35
Q

fuse/circuit breakers

A

melt when current is too high to stop shocks or fires

36
Q

circuit breaker more convenient than fuses because

A

switch- faster

switch-can be switched back on, fuse has to replace

37
Q

power =

A

current x voltage

Pee on the IVy

38
Q

energy transferred =

j

A

current x voltage x time

Ee on the IVy Tea

39
Q

Resistance =

ohms

A

Voltage/current

40
Q

diodide

A

graph goes steady then upwards curve
high resistance one way
current the other way

41
Q

metal filament lamp

A

curve then constant up then curve

42
Q

wire

A

current through a wire is proportional to voltage

43
Q

LDR light dependent resistor

A

line box with arrows line
downwards curve, resistance decreasing with light intensity
resistor used in light sensing units

44
Q

thermistors

A

line- box with line through on a diagonal -line
a temp-dependent resistor
temp sensors
hot conditions, resistance drops

45
Q

charge =

charge measure in coulombs C

A

current x time

46
Q

series circuit

A

all components one after the other along the wire
disconnect and circuits breaks
fairy lights
current same everywhere

47
Q

parallel circuits

A

disconnect one and will hardly affect others
each component has its own loop
how most things are
household lights

48
Q

one volt is

A

one joule per coulomb

49
Q

static electricity cause

A

caused by friction
two insulators rub each other
one + electrostatic charge loss electrons
one - electrostatic charge gain electrons
which way depends on material

50
Q

+ +
+ -
- -

A

repel
attract
repel

51
Q

charged rod test

A

suspend a rod with known charge
bring another rod towards it
if attraction, test rod has opposite charge of suspend rod
if repel, test rod is same charge as suspend rod

52
Q

generators that make your hair stick up

A

Van de Graaff generators

53
Q

static helpful

A

inkjet

photocopier

54
Q

static problem

A

lightning

fuel (gas stations)

55
Q

1 amp

A

1 coulomb per sec

56
Q

voltage =

A

energy/charge

57
Q

electron charge

A

-1