Physics

Question 1

Remmeber displacment is the minimum straight line distance between two points
And what about the graphs

Answer 1

Displacment is under the graph for velocity, distance add, displacment subtract

Question 2

Terminal velocity ideas

Higher mass =? (For same volume)
Open parachute

Answer 2

When weight = drag resultant force is 0 so you continue at that velocity which is terminal
Higher mass, I guess lower drag to mass so more resultant
If you have a greater mass you have greater weight so greater drag needs to counter and as drag propeitnsk go v 2 that means you’ll have a greater TERMINAL VELOCITY for the same volume

2) open parachute then the drag force is higher than weight so resultant force upwards so deceleration slow down so drag slows down until ti atches widght snd now at nee terminal velocity which is led

Question 3

Remember moments =

Answer 3

Firce x perpendicular distance from force to pivot!

Question 4

Pressure in liquid

Answer 4

Height x gravity x density

Indeed net of cross sectional area etc

Question 5

Upthrust and what it represents

Answer 5

Different pressures acting at bottom and top, multiply by cross sectional area CN different force resulting in upthrust

Question 6

Total pressure

Answer 6

Atmospheric and water

Question 7

What is Archimedes principles

Answer 7

That upthrust acting on an object is = to the weight of the fluid dispersed

As h x area is volume d x volume is mass and mass x gravity is weight of fluid !

Volume of fluid and volume of object dispersed is always = howeber

Question 8

For an object to float sink

Answer 8

Float the upthrust = weight
Or else it will sink until it can

And if it still can’t then it will fall

This is because of densities

If density if one bigger than other it will fall

How far it falls can also be determined by what’s being submerged density / the liquid density
So 90 / 100 = submerged until 0.9m is down leaving 0.1m ontop

Just know if it floats then weight is = upthrust so weight of fluid

Question 9

Power = force x velociy when

Work done =

Answer 9

In constsnt velocity and force in a straight line where velocity is mainted

Work done = force x displacment in dedication of force so force x cos they

Question 10

Force extension graphs

Answer 10

Force is prorotinsl to extension until proportionality limit, then no longer propritnsk but still elastic, then work done is to deform and inelssfoc

Energy = 0.5fx or kx 2, strain energy same thing rearrange flax for it

Number density is area in stress vs strain graph

Stress = f/a , strain is x/L

Gradient on force extension graph = spring constsnt which idea of stoffness

Question 11

Spring constsnt parallel series

Answer 11

In parallel, the spring constsnt actually adds as harder to pull
In series it’d 1/x type thing as easier to pull

Question 12

Young modules?

Answer 12

Jus another prompts if each material independent if shape and size, gives an idea for stiffness agsin

Ultimate tensile strength id measure of how strong an object is, thr max stress it can twirl before it breaks

Young mud Luke’s is gradient

Question 13

Why do you want time to increase in a crash

Answer 13

As force is change momentum / time, you want max time to reduce force for the same change in momentum

Question 14

Is impulse conserved

Answer 14

Yes because impulse = change of momentum

And also if I hit d9 etching force third law same force applied and time of contact always same so impulse actually gonna be conserved too

So if impulse is conserved, then momentum is too

Question 15

Ohms law

Answer 15

When temperature is constsnt,
- current in a wire is proportional to the voltage

Question 16

Why does I V graph of filament Kano change

Answer 16

As current increases heats up, kinetic energy cause metal ions to vibrate and act as impediment, this increases resistance so decreases voltage, thus filament lamp kinda levels off

Question 17

Diode
Resirivty

Answer 17

Diode takes voltage then let’s through infinitely, gradient goes to infinity 1/ inifnty is 0 resistance, on other end infinite reisdrsjcem

Different wt different temperatures but a constsnt for each material, resistance = resitivity x length / Area

Conductors have higher standards then it goes down

Again with TEMPERTAURE for conductors it decreases whatever semiconductors acc increases a number density increased too

Question 18

Thermistor and dlr

Answer 18

Negative temperature thrimstor means increase of temp reduced resistance as number density increases letting more electrons increasing current decreasing resistance
Tmelerture 8 beer ti resistance
Same for ldr

Question 19

Why are volts lost

Answer 19

When current in a poor source, work has to be done by the charges as they move through thr power source , in a chemical cell dome by reactions

Anyways for internal resistance jus split between normal,y

If it’s a battery then in series the resistances and the voltage add, but in parallel the voltage the same but the resistance divide accordingly giving more current p, and other more voltage

The emf measured is when the switch is off and no current
Remember a switch causes a bypass

Remember rearrange e = V + Ir for two vs,he’s we can acc measure = current and terminal pd , such that gradient is negative r and intercept is emf . Here shoes when ai is 0, terminal of is emf

Question 20

Why would you need higher currents or lower and so can minaipulte batter system

Answer 20

Higher currents to charge something quickly or start a car, lower currents for safety like in class, still provided high voltage, but low current did so

Question 21

Potentiometer, where gives you higher v out snd lower

Answer 21

BASICSLLY arrow represents how much if the resistor is used, so all thr way means all the resistor voltage going to the outer circuit, but closed means none of it

Question 22

Earthquake waves p and s are

Answer 22

P is transverse , s is longtifunal
Transvers waves has its oscillations at right angles to direction of energy transfer
Lomgifunsl waves socialite parcelled to energy transfer

Progressive waves are waves test trnssfer energy without transfering matter,
No matter is displaced, a resorijg force always acts to bring it back where it was if a medium was involved

Sound waves and S waves lingtifunsl, spring too, em , p waves etc transverse

Only transverse waves can be plane polarised as they socialite in two Llanes, longijfnsl waves are already

Question 23

How do lonttimfusk waves and transverse vibrate with what

Answer 23

Transverse peaks and troughs, lontinfunal compressions and rarefactions ,

Question 24

Remember when using wavefronts what represents wavelength and thus what to be wary in refractions

Answer 24

Need to be wary thst distance between wavefronts is wbskentgh so if refracted to faster medium and wvskentgh increased actually bugger gap between the wavefronts is needed

Remember deeper what is faster water

Question 25

When a wave refracts whatnalways happens

Diffraction

Answer 25

Also reflection and partial polarisation here

Is when a wave spreads out around a gap, the smaller the wave is compared to the gap terms of wavelength the greater the diffraction,

Polaeodsorommosmehen oscillations are confined to one plane, can be a component of that oscillation in one plane yea that’s calm, but if it’d 90 then it won’t

Light jd unoloarised

Longitnfusk csnr be olaorised as they already oscillate in a single plane

Question 26

Itneidty

Answer 26

= power/ area, where area = 4 pi r2 assuming area of a sphere, and sitsnce from centre is r

Intensity is propritnsk to amplitude squared too, so if amplitude increases in superposition, intensity will too and be louder brighter etc.

This is why we allign aerials, to allign ti apcstch differnt aligned waves that have been polarised ti reduce interference

Intensity also propritnsk to cos theta squared

When you reflect partially polarise so light often comes off card horizontally so sunglasses horizontally plane polarised

Question 27

What is constructive intervene destructive

Answer 27

When supoerpose in phase , constutivbe, when antiphase and hspoerpose, destructive interference
Amplitude decreases to 0 and thus so does itnneidty snd quite or dark

To produce a constsnt internecine pattern the waves must be coherent meaning CONSTANT PHASE DIFFERENCE and of same frequency

Question 28

What does being coherent mean

Answer 28

Constsnt phase difference not in phase CONSTSNT PHASE DIFFERENCE

Question 29

Interference patterns constsnt then

Answer 29

Where meet in phase supervise constructively to form a maxima , and opposite too

The path length difference as a fraction if wavelength can let you know if maxima or what. If this is a whole inter of wavelength then constructive,if half then destructive and minima. From centre it starts with minima maxima etf

Question 30

Young double split

Answer 30

Was done to prove light has priorities as a wave rather rhwn stream of tiny particles like Isaac newton said

Double slit from same source thst was filtered produces coherent waves sd came form same point source. Diffracted once and then again produced two sources of coherent waves thst duporrpose with each other forming a constsnt interference because it’d coherent

The fact what this dupeorspded showed light as a waves, in fringe pattern.

Assuming the distance from slitd and screen is much bigger than dlit superstition, which gotta be small anyways to diffract as comparable to wavelength of light, then wavelength = ax/d
Here x is the soerstion between two consecutive minima or maxima

Only nolds of coherent snd.d is bfffer then a

Question 31

Conditions for a stationary wave

Answer 31

Two progressive waves travelling opposite each other with the SAME FREQUENCY superpower
(Opposite and same frequency)
- where they meet in phase due ti same frequency cindtutively supervise to form an snitnide snd where they form in Antiochus’s destructively to form a node

The distance between two consecutive nodes is equal to half the wavelength of the orientalist wave , freuwncynis thr dwme however

Question 32

Differences

Answer 32

As they are travelling opposite
-no net energy transfer compared to progressive waves
- objects between nodes are in phase and on either side of nodes are in antiohsse,whereas phase varies in the whole, cycle
- wavkentgh is point two seucceuvie points in phase , whereas distance between nodes is half
- amplitude is thr swme at every part of the progressive wave whereas maximum at Antonine and min at node

Again
No net energy fomsprerd to energy
- phase difference exams betweennode and opposite ends not , whereas changes through out scycel
Amp,iTunes same fir orrissidge max and min
Wavkentghs tok

Question 33

Why can not all frequencies producenststika ray waves
How is a stationary wave made

Answer 33

Based on a systems mass tension etc only certain frequencies can form stationary waves

Amoluck on a string causes a progressive wave tohstntrwbekd to the end where it gets reflected 180 to form teomprorfeevie waves of same frequency theta supoerpose opposite to each otjer

The smallest frequency thst csn is thr funsmentsl

In s system with both closed ends, speed is constsnt esch time .
Two nodes system thr lentgh if the string is equal to sums of the half wavken5ghdb
So can find out freuwnecies and see that they are integer multiples of each other fine

Question 34

With one open and one closed what freuwneices are positive

Answer 34

You can make some closed end one open system using water and a tube to change the lengths, then create a stationary wave by vibrating thr air with a pitch fork where. Urbstions firm stsinsry waves too

One open one closed only produced odd integers multiple of the final mental , because always extra 1/4

And for both open simsilar to before

Question 35

What happens when telmpoudspeakers connected from same source

Answer 35

They will supersede and since same source then coherent so constsnt interference so areas of minima and miss I sound from the central point where the meet in blasé w d a jtlnsde

However further out you go thr wmokituded begin to spreading out over large distances, Doppler effect, do smplituded thst resvh will be different snd effect is now less ntocisble