PAPER 2 - practice questions Flashcards

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1
Q

explain when an object might topple over

A

centre of mass is the point at which the weight of an object acts through.
an object will topple over whn the centre of mass falls outside the base of the object

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2
Q

describe what can effect the stopping distance of a lorry

A
  • stopping distance is thinking distance plus braking distance
  • thinking - tiredness, distractions, drugs or alcohol
  • breaking - condition of tyres, condition of brakes, wet/icy - less friction, heavy and fast it will take longer
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3
Q

explain how an egg dropped into a polystyrene foam prevents the egg from breaking

A
  • soft foam increases the time it takes for egg to stop
  • this decreases the rate momentum changes which reduces the force on the egg
  • as this force is reduced the egg doesnt crack
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4
Q

explain in terms of conservation of energy what will happen when a person dives from a stationary boat

A
  • momentum before is equal to the momentum after
  • before mom of boat and diver is 0kgm/s so after it must be 0 too
  • after driving the person has a small velocity and momentum in forwards direction
  • therfore boat will have the same in the opposite direction
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5
Q

identify what happens to pressure with increasing altitude

A
  • altitude increases pressure decreases
  • bc pressure is molecules colliding with a surface
  • and so as the altitude increases the distance between molecules increases so at a higher altitude there are fewer molecules
  • so the number of collisions with the surface decreases
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6
Q

what happens to pressure with increasing depth

A
  • as depth increases pressure increases
  • bc increasing depth increases height of water above
  • which increases the force of water from above
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7
Q

explain how upthrust occurs

A
  • object in water will experince more pressure at bottom than top
  • bc part thats deeper under water has a greater height of water above it exerting a force
  • this difference in pressure creates a resultant force which is upthrust
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8
Q

compare sound waves with x rays ( any longitudinal wave with transverse)

A
  • sound waves are longitudinal so parallel
  • x rays are tranverse so perpendicular
  • sound waves cant travel through a vacum but x rays can (all tranverse waves can travell throguh vacuum)
  • sound waves travel slower
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9
Q

compare the use of x- rays and ultra violet light

A
  • x rays detect broken bones, locate bullets and detect dental problems and kill cancer
  • ultraviolet - pre natal scanning, remove plaque from teeth, steralise, give suntan, security pens
  • x rays ionising and can mutate dna and damage cells - cancer
  • ultra violet is the same
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10
Q

describe the apparenece of a red object in a room with green light only

A
  • red object would NORMALLY appear red in white light bc it would reflect red parts of the spectrum and absorb everything eklese
  • BUT IN GREEN LIGHT - it will absorb all green light and no reflect ANY LIGHT AT ALL
  • so the object will apear black
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11
Q

explain how you could determine if a substance is magnetic or non magnetic

A
  • put it next to a permanent magnet
    1. if it has no effect then it is non megnetic
    2. attracts or repels - it is megnetic
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12
Q

describe how to plot magnetic field patterns around a bar magnet

A
  • put magnet of paper and outline the bar
  • put a dot by a pole of magnet and put compass on dot
  • put dot at tip of compass needle and move compass tail to new dot
  • repeat until it reaches the other pole of magnet
  • then draw lines through the dots and add arrow from north to south to show direction of field lines
  • repeat starting at dif starting positions
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13
Q

explain why compass needles move when placed near a bar magnet

A
  • bc the compass needle is a small bar magnet so they exert a forc on each other
  • so they can attract or repel each other
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14
Q

explain why the wire moves when the switch is closed for the motor effect

A
  • when switch closed the wire has current bc circuit is complete
  • this creates mag field around wire
  • this interacts with permanemt field of magnet
  • creating a force on the wire causing it to move
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15
Q

describe how to build and test and electromagnet

A
  • wrap a coil of wire around an iron nail or core
  • connect wire to power supply with crocodile clips and turn it on
  • to increase the strnegth - more coils, more current
  • to test use paperclips and see if they stick to it and if more stick to it when you increase the strength
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16
Q

exlain why a star remains stable

A
  • bc the expansion of a star due to fusion is in equilibrium with the gravitational collapse
  • so the inwards and outwards forces are equal
17
Q

describe what happens to a small star when it leaves the main sequence group

A
  • turn into red giant
  • so surface temp decreases and relative luminosity increases
  • this then turns to a white dwarf when the tmep increases and relative luminosity decreases
  • then this fadesout gets cold and becomes a black dwarf
18
Q

the universe contains a large variety of different elements. describe how this happened

A
  • fusion takes place within stars and hydrogen is turned into helium
  • this fusion continues and formed large elements
  • these elements heavier than iron were formed in supernova and scattered by the explosion
19
Q

describe how our sun formed

A
  • dust and gas pulled together by gravity
  • as more mass pullet together it got really hot
  • when it got hot enough hydrogen nuclei fused together and released energy as heat and light
  • this energy caused an expanision which balanced the gravitational pull
20
Q

describe how. a massive star will change at the end of the kian stable period

A
  • turn into a super red giant, the supernove, the neutron star then black hole
21
Q

why will the sun not undergo a supernova

A
  • because its a small star NOT A MASSIVE STAR
  • and only massive stars undergo supernova
  • instead the sun will turn into a red giant then white dwarf then black dwarf
22
Q

explain evidence for the big bang theory

A
  • galaxies show red shift
  • more distant galaxies show a greater red shift
  • galaxies are moving away from earth and universe is explading
  • BC THE DISTANT GALXIES ARE MOVING AWAY FASTER this shows that the universe began in one place
23
Q

explain how the light of an approaching galaxy may appear changed on earth

A
  • the light will appear to have a shorter wavelength and the frequency will have decreased. the light will have undergone blue shift (the other direction)
24
Q

explain what red shift and the size of red shift tells us about the galaxy

A
  • red shift tells us its moving away from earth
  • size of red shift tells us how fast and how far the galaxy is
  • the greater the red shift the further and faster the galxy is