Extra Flashcards
(115 cards)
1
Q
Magnet be replaced by a much stronger magnet magnet a remains the same describe how you would redraw the arrows on the diagram to show the repelling forces and their interaction
A
Both arrows need to be longer
Need to be the same size as each other
2
Q
What is mass?
What is weight?
What proportion is weight and mass?
A
-The amount of matter in an object
-weight is due to the force of gravity
-Weight of an object is directly proportional to mass
3
Q
What is meant by the term of centre of mass?
A
Point which you can assume where the mass of an object acts
4
Q
Why shouldn’t a rusted must be used in an experiment?
A
The mass may not be the same as it is labelled previously
5
Q
State the type of art that is introduced to the results when using a tray and a newton meter to measure the mass?
A
-systematic error
-Because the weight of the plastic tray will be included in the weight of the mass
6
Q
What does the gradient mean in Graph?
A
-of the units based on the equation for gradient will give the other thing included in the equation
7
Q
What does work done against frictional forces on the wheels do to the temperature?
A
Temperature increases because doing work transfers energy and some is dissipated into the thermal stores
8
Q
What are the three things that can be done to an elastic object to deform it?
A
Compression bending and stretching
9
Q
What type of proportion is the extension to the force in elastic objects?
A
Directly proportional
-Assume that it hasn’t reached the limit of proportionality
10
Q
What is the key point about moments?
A
Total anticlockwise moment must equal the total clockwise moment if it is balanced
11
Q
Why would a student apply lubricant to the pivot to reduce the frictional forces acting on it?
A
The object is able to rotate freely about the pivot, so it balanced due to the moments that are being applied and not the restrictive forces
12
Q
Describe an experiment method to investigate moments?
A
Hang 100 g hundred mass on the left arm of the bar and record its mass and distance from the pivot
Hang another 100 grand maths from the right arm of the buy any distance from the pivot observe wether, it is balanced
Move the mass on the right arm of the bar to different distances and record the mass, and any distance from the pivot where are the mass balance is the bar
Add another pinch of ground to the hanging mass on the right arm again move. This must along the right bar, until it is balanced, record the mass of the distance from the pivot.
Repeat the balancing process for different masses hung on the right arm and on the left arm
Calculate the moments for each pair of balanced masses, you record
Compare each anticlockwise moment to the clockwise moment that balance is it there should be equal
13
Q
Explain why water, escaping from the bottom of the spout can go faster than the rate at the top?
A
Pressure increases with death as there is more water molecules, causing more weight which contributes to the pressure causing the force pushing the water out to be larger increasing the rate
14
Q
Suggest why the depth experience is different pressures in freshwater and seawater, despite swimming at the same depth
A
Pressure at a given depth depends on the density of liquids
seawater is denser so is a higher pressure
15
Q
What is the speed of sound?
A
330 m/s
16
Q
What type of quantity is displacement?
A
Vector quantity
17
Q
Explain why the weight of a golf ball appears to change when placed in water?
A
ball is submerged in water
upthrust acts upon the ball.
the force acts as an opposite direction to the ball weight
combining forces leads to the ball appearing to weigh less
18
Q
Why would an object sink?
A
Upthrust acting on the object is equal to the weight of the water that the necklace displaces water has a much lower density than silver. So the weight of the displaced water is less than the weight of the necklace. This means that up for us acting on the necklace is less than the weight so it sinks
19
Q
Why does atmospheric pressure decrease with altitude?
A
-earths atmosphere is a thin layer of air around the Earth
-Caused by the air molecules which exert force on the surface
-As the altitude increases, the atmosphere gets less dense as there are fewer air molecules
-This means less collisions, less force and less pressure
-Weight air molecules above the surface atmospheric pressure and because there are fewer as the altitude increases the weight above the surface also decreases
20
Q
Explain why a Satellite orbiting has a a unconstant velocity?
A
It travels at a constant speed (scalar) , but changes direction, so the velocity (vector) is not constant
21
Q
Suggest one way that students can make timing is more accurate?
A
-Same point on the boat
-Use a stopwatch
-things made close to the boats to avoid Parallex Error
22
Q
What does a rollercoaster decelerating at an increase in the rate look like on a graph?
A
Curved decreasing
23
Q
What do you do if you have to work out the distance travelled and they are not full sqaures?
A
1-find the area of one square
2-multiply for the estimated amount of all squares
24
Q
Advantages and disadvantages of light Gates?
A
Advantage
-Like it’s measure speed, and Time, accurately to a high resolution
Disadvantage
-Measurement over large areas can miss changes in accelerations
25
What is terminal velocity?
-The resultant vertical force of an object falling at terminal velocity is zero
-Terminal velocity is the maximum velocity of an object that it can fall at
26
Explain why both objects eventually fall at constant velocity and white terminal velocity of the book is lower than velocity of the ball?
Has the object falls it accelerates due to gravity increasing velocity
Resistant also increases and is in the opposite direction to acceleration
Eventually, resultant force will be zero, and this is constant velocity (terminal velocity)
If an object has a larger surface area, there’s more air resistance so reaches resultant force of zero sooner and has a lower terminal velocity
27
What is Newton’s first law for stationary object?
If the resultant force of a stationary object, zero, it will remain stationary
28
What is the acceleration of an object directly proportional and inversely proportional to?
Directly=Resultant force acting on the object
Invserly= mass of an object
29
What can air resistance also be called?
Drag
30
What does it mean when an object is constant?
Resultant forces, zero
-remember for calculations
31
What is a normal contact force?
When someone pushes down on something
32
What inertia and inertial mass?
Inertia= tendency to continue in the same state of motion
Inertial mass= how difficult it is to change a velocity of an object is
33
Why were changing the force and changing the mass not correctly show the relationship between the mass and acceleration of a trolley?
Your test and affects of varying mass and very into force on a trolley. One of them has to be constant, so you cannot find the effect of one if both were changed.
34
What is the thinking distance?
What is the breaking distance?
How do you find the stopping distance?
Thinking distance is the distance travel during reaction time
Breaking distance, is the distance travelled under braking force of the vehicle
Thinking distance add breaking distance = stopping distance
35
How does a vehicles breaks work? (Temperature)
Work done by friction between breaks, and wheels transfers energy to the thermal store of the breaks and increases temperature
36
Why is it important for cars? Have brakes and tires that are in good condition. Explain how this would affect the stopping distance and safety.?
-The tread depth on tires removes water
-Large amounts of grip (friction) between the tires and road
-is breaking distance in wet weather
-Less likely to skid
-Larger, braking force applied smaller, breaking distance
-Good condition is less likely to overheat under a large braking force and is less likely to cause a crash
37
Describe one of the method that can be used to test peoples reaction times?
Clicking a mouse on a computer screen when it changes colour
38
Explain safety implications for a person who is listening to loud music and is inpatient at night?
Distracted increases reaction time
Increased reaction time increases the thinking distance
Driving quicker increases the distance travelled by the car during the reaction time
The stopping distance increases as it won’t be able to stop in time
Unable to see in the dark and tired and can’t hear is it has it increasing reaction time
This reduces the stopping distance needed to avoid hitting your hazard and may lead to a collision
39
Use conservation of momentum to share newtons cradle?
Total momentum in the system is equal to the mass of the moving ball multiplied by its velocity as it hits the line of balls it transfers the momentum to the rest of them and comes to a stop.
Find it reaches the last ball. This final ball has the same momentum as the first ball, causing it to move with the same velocity because they have the same mass with the same velocity.
40
Why is it difficult to have the same speed for each vehicle?
Difficult to set the vehicles moving with a constant speed, so it may take many tries to get another measurement of the same speed
41
Why would I think last one of the vehicles make the experiment not as effective?
The mass of the vehicle gets to launch it will not be held up by the air jets on the track, so will cause friction forces making this result for the speed of the vehicle less accurate
42
What is an object momentum equal to?
Resultant force acting on the object
43
During a collision, an airbag is activated in the car, explain how the airbag reduces the risk of the driver been injured during the collision
The airbag increases the time taken for the drive to stop this decreases the rate of change of momentum. The force exerted on the driver is equal to the rate of the change of the momentum so the force on the driver is reduced a lot of force means to lower risk.
44
How to do equations involving changes of momentum?
1-find the momentum in the first system
2-find the momentum in the second system (this one should be negative if it is moving in a different direction to the first one)
3-find out the total momentum of both systems, combined by minus in the large one by the smaller one
4-then find the momentum of the system after the event do this by combining the weight and using the momentum (step 3) before the previous one put into the equation, this will give you the magnitude of the velocity
45
Give one example of transverse waves?
Electromagnetic waves
ripples on the surface of water
light
46
Suggest a way that she didn’t come measure the distance between recalls that on moving, suggest and explain what the student could do to make it easier?
strobe light
when the frequency of the strobe light matches that of the wave reference will appear stationary, and the student can measure them there
47
Describe a method to measure the speed of waves on a string?
1. connect the string over a pulley to a vibration transducer
2. Connect a signal generator to the vibration transducer and switch it on.
3. Adjust frequency of the signal generator to produce a clear waves is on the string.
4. as many halfway waves on the string, as you can measure the distance, they cover.
5. Divide this number by the number of half wavelength to find out the average half wavelength on the string.
6. Double this value to find the wavelength of one note down the frequency on the frequency generator.
7. equation to figure out the speed
48
A wave is reflected
A wave is absorbed
A wave is transmitted
It’s bounces off the material
It transfers all the energy to the material
It passes through the material
49
Explain how having lower increments on ray box over the protractor will improve results?
The beam is narrow than the distance between the protractor, so it’s easier to measure angles to the nearest degree, and there is less likely to be human errors so will be more accurate
50
Why would the angle of incidence not equal the angle of reflection?
The error could have been that the normal was not drawn perpendicular to the mirror
51
Describe an example of an infrared radiation, transferring energy from a source to an absorber?
Energy is transferred for the family energy store of a toaster heating element by infrared radiation to the thermal energy store of the bread inside the toaster
52
How is light reflected on a rough surface?
Rough surface means that the angle of incidence is different for each right across the width of the beam
This means that each rate is reflected in a different direction, so the light is scattered
53
Explain how a light box is used to investigate light and what are the apparatus could be used
Hooray box was used to provide a thin beam of light so that the angle of incidence of reflection can be easily measured.
-laser
54
Explain how the speed of light rays changes as it passes from air to the glass block?
The speed of the light rays decreases as the angle of refraction is smaller than the angle of incidence as it bends towards the normal
55
Why does water change the speed of light, the least?
Water has the largest angle of refraction, so has bent the light the least, so has slowed down the light
56
Explain wall experimenting with liquids in the refraction experiment. The container should have thin walls.?
The material of the container will also refract light the finish the walls of the container, the mess this will affect the results
57
How do you longwave radio waves follow the Earth curved surface?
Diffraction
58
Describe how electrical signals generates radio waves in TV signal transmitters, explain how this radio waves can generate an electrical signal and distant TV aerials?
An alternating current flows in in the circuit of the transmitter it is connected to
alternating currents are made up of oscillating charges of electrons
As the electrons oscillate in the transmitter, they produce oscillating electric and radio waves
radio waves are transmitted to, and then absorbed by distant TV aerials
The energy carried by the way, this is transferred to the electrons in the material of the receiver
This causes the electrons in the receiver aerial to oscillate
This generates an alternating current an electrical signal
Alternating-current has the same frequency as the original one used to generate the radio wave
59
Explain the differences between longwave, radio, waves and shortwave?
Short
The receivers must be in direct site from the transmitter, as the wavelengths are easily absorbed by objects
Long
They can be transmitted over long
Diffract around the curved Earth surface
Diffract around obstacles
60
How do you microwave cook potato in the microwave oven?
Microwaves are absorbed by water, molecules in food, transfers energy to the water, heating up the water in the food
The water than transfers energy, they have absorb to the rest of the molecules in the food, cooking it
61
Explain why microwaves there is a difference in temperature of the food on the plate. It is on?
The glass plate does not absorb any microwaves as it does not contain water molecules, and so it is only heated by conduction from the potato
62
What are the type of electromagnetic wave can also cook food?
Infrared radiation
63
Compare the differences in normal cameras to infrared cameras?
-When it is dark there is very little visible. Light for normal camera to pick up.
-How about a person trying to hide is warmer than surroundings, submit a more infrared radiation, so he’s able to be found out as it stands out
64
What are the uses for UV rays?
What are the uses for visible light?
What are the uses for x-rays?
What are the uses for gamma rays?
UV rays= artificial, sun tanning, energy-efficient lightbulbs, revealing invisible ink
Visible light = fibre-optic data transmission, energy-efficient lightbulbs
X-rays = medical imaging of bones., cancer treatment
Gamma rays = cancer treatment
65
How can a medical tracer be used to create an internal body image?
Why are gamma rays used?
The patient is injected with a gamma emitting source
Gamma radiation is detected outside the body which is used to follow the sources progress around the patient’s body
-They can pass out of the patient’s body
66
Explain how x-rays are used to form images of a patient skeleton?
X-rays are directed at the patient. The x-rays are absorbed by the bones.
They are transmitted by less dense body material, such as Flash, the screen behind the patient text. The x-rays, and a negative image is formed.
Right at ours were fewer x-rays are detected
67
What is safety precautions? Should medical workers take when using x-rays and gamma rays?
Let aprons stand behind a lead screen leave the room what’s the treatment is taking place
68
Describe how x-rays and gamma rays can cause cancer?
The transfer so much energy to living cells that they cannot of electrons. An ionised atom. Is this causes mutation of jeans which lead to cancer.
69
How do you lenses focus light
Refracting light
70
How do you know when something is a real image?
The light rays come together to form the image
71
Lenses that has formed a virtual image is now the distance of two focal lengths away from object what is different about the image formed?
It is a real image now
It is smaller
It is inverted
72
What does the term opaque mean?
Opaque objects, do not transmit, light,
Light which hits them is either absorbed or reflected
73
What does a white object to what does a black object to?
A white object reflects all light waves equally
A black object, absorbs, all light waves
Red= reflects red only
74
When a red object and white object scene for a green filter, what happens?
The white object reflects all colours of light so appears green
The red object looks black, because it is only reflecting red light, which is absorbed by the green filter
75
What happens to a transparent object?
Doesn’t absorb visible light
76
What does the absorption graph of a perfect black body object look like?
Just a straight line across 100% mark
77
What is the best emitter of infrared radiation?
What is the worst emitter and absorber of infrared radiation?
How can you improve an experiment on infrared radiation?
-Matt, black
-Shiny/glossy white
-use a radiation detector radiation use a ruler to make sure he measures the radiation emitted from each side from the same distance
78
What is the perfect black body?
An object that absorbs all of the radiation that hits it
79
A white star expands and its surface area appears red in colour. Describe how the surface temperature of the star has changed.
It has gotten cooler
80
Electromagnetic radiation from the Sun affect the temperature of the explain with respect to radiation emitted by the Sun and the Earth. How the temperature of the Earth remains constant
During the day, the half of the Earth which is facing the Sun is hit by radiation emitted by the Sun
Some of this radiation is absorbed by the atmosphere of the Earth surface
Because the statement of radiation absorbed during the day is greater than the amount that is omitted
This causes an increase in the local temperature
The half of the Earth, which is facing away from the Sun has no radiation from the Sun, hitting it as it is night time
This half of the Earth absorbs very little radiation, emits, radiation, Normal, rate
So at night the radiation emitted is there a much higher rate than it is absorbed
This causes a decrease in local temperature
Throughout each full cycle of the day and night, 1/2 of the Earth will be increasing in temperature, and the other half will be decrease in temperature
How old is local temperature is changes and balance out, so the average temperature of the Earth remains roughly constant
81
What is the range in frequency of normal human hearing?
Describe the function of the eardrum in the air ear?
What happens to the wavelength and frequency of a sound wave as it passes from an air to a solid material?
20HZ- 20KHZ
Eardrum vibrates, when the sound waves vibrate the air inside the ear, passing these oscillations onto the rest of the ear
The frequency stays the same, and the wavelength increases
82
pot and string how is soundwaves transferred, so it can be heard on the other side of the pot?
Someone speaks and produces a soundwave
The particles in the air, vibrate, back and forth, compressions, and rarefractions as it travels through the air to the pot
When the sound waves hit the pot, the air particles hitting the base of the pot, cause it to move back and forth and vibrate
This causes particles in the end of the string tied to the pot to vibrate
The particles in a string vibrate and transmit the wave along the string
When the vibrations reach the other end of the string, they are transmitted to the base of the second, for this course, is the surrounding air particles to vibrate generating a sound wave, which is heard by the second child
83
What is the definition of an ultrasound?
Vibrations with frequencies that are too high for humans to hear
84
How do ultrasound create an image of a fetus
Pulses of ultrasounds by directed towards the fetus, when they reach the boundary between the fluid of the room, and the skin of the feet as they are partially reflected their reflections are detected and their timings and distributions are used to produce a video image
85
What are the properties of S waves and P-waves?
P-waves
Can transfer energy through the Earth
Longertufial
Can pass through liquids and solids
S waves
Can transfer energy through the Earth
Transverse
Can only pass through solids
86
Explain how seismic waves can indicate that the earths core is made from liquid
Seismometers from different areas can detect seismic waves if there are no S waves something is stopping them as the S waves cannot pass with a liquid, so it’s likely that are part of the interior of the Earth is a liquid state
87
Why does the velocity of the seismic waves change as they transfer between mediums?
As they pass between a solid and a liquid medium, they travel at different speeds in solids and liquids, so the experience sudden change in velocity
88
Steel paperclip is placed against the block of cobalt when it is near a bar magnet what happens?
What happens when the bar magnet is removed?
The block of cobalt becomes an induced magnet when it is placed in a magnetic field of the bar magnet which causes a force of attraction between the paperclip and the cobalt
Call boat demagnetise
89
Explain how compass can be used to determine the magnetic field of a magnet
Needle of compass points in the direction of the magnetic field it is in
Put the magnet on a sheet of paper
Move the compass along the field lines of the horseshoe magnet
Mark the direction of the compass needle at each point and join the marks up to create a diagram of the magnetic field lines
90
What happens if a compass is moved away from all of the magnets?
It was a point to the north, because it is a lining itself with a magnetic field of the Earth
91
State the differences between permanent and electromagnetics?
Permanent magnets always have a magnetic field, but an electromagnet can be controlled and turned off by an electric current
92
Describe the magnetic field inside the centre of a solenoid?
The magnetic field is strong and uniform
93
State, one way in which the magnetic fields of a strength of a solenoid can be increased
Put a iron block in the middle of the solenoid
94
What happens when the north pole of a magnet is brought near the current carrying solenoid?
It is repelled, because the direction of the current means that the left-hand of the solenoid access the North Pole, like poles, repel
95
Explain how the circuit uses electromagnetism to sound a bell?
When the switch is closed, the current will flow in a circuit
The electromagnet will switch on and become magnetised. This will attract the iron.
Which will swing the arm on the pivot and cause the hammer to ding the bell
When the arm pivots, the contacts will move apart from each other, breaking the circuit the current. Will stop
The electromagnet is demagnetised
The iron will no longer be attracted to the electromagnet, so the arm swing back to its original position
This will be complete the circuit and the process will start again
96
What causes the motor effect?
The motor effect is caused by the magnetic field of the current carrying wire, interacting with a magnetic field of the permanent magnets
97
State three factors which determine the magnitude of the force acting on the wire
The magnetic flux density
The current flowing through the wire
The length of the wire in the magnetic field
98
How do you speaker loudspeaker work?
An alternating current is passed through the coil of wire.
The coil of the wire is surrounded bye permanent magnet and attach the base of a paper cone
When the coil carries a current is experiences of force, so the paper cone moves
this allows variations in the current to be converted into variations in the pressure in soundwaves
99
Why does a coil turn in a motor?
The interacting magnetic fields of the coil and the magnet causes a force on each arm of the coil in the opposite direction
100
How can a DC current be used to make a coil continue to rotate in the same direction?
Swap the contacts every half term, using a split ring communicator to reverse the direction of the current this watch the direction of the forces of each arm and keeps the direction of the rotation constant
101
When are the two times that potential difference is induced?
When an electrical conductor move relative to a magnetic field
When there is a change in the magnetic field around a electrical conductor
102
How can the generator effect power things?
As the bike, wheel turns, the generator wheel on the device is turned this causes the magnet to rotate the coil of the wire experiences, a change in the magnetic field, which induces a potential difference.
The wire to the lamp form a complete circuit and so a current is induced.
103
What do alternators use and what do dominoes use?
Alternators use slip rings and brushes and generate AC
Dominoes use a split ring commutator and generate DC
104
Describe how in a microphone sound wave is converted into electrical signal
The diaphragm is attached to a coil of wire, which is surrounded by a permanent magnet
When the sound waves hit the diaphragm diaphragm moves this intern course is the colour of the wire to move relative to the magnet
Which induces a potential difference and so a current an electrical signal
105
How does current flow in a transformer?
An alternating current is applied across the primary coil
This causes a changing magnetic field in the iron core
This changing magnetic field induces an alternating potential difference in the secondary coil
If the secondary coil is a part of a complete circuit, this causes a current to be induced
106
During the experiment of the properties of transformers, the secondary cool has been worn through and is now replaced. Why is it important?
If the exposed word came into contact with the iron core, it would cause electricity to flow through the core leading to inaccurate results
The exposed wire could also cause an electric shock
107
What is the sequence of a star that is way bigger than the Sun?
Nebula
Protostar
Main sequence
Red supergiant
Supernova
Neutron star
Black hole
Stars that have a similar mass to the Sun make a red giant, which goes to white dwarf and black dwarf
108
How does nuclear fusion working stars?
As the protostar ages, it’s temperature and density increases. This causes particles to collide with each other. More often when the temperature gets hot enough hydrogen nuclei fuse together and create helium nuclei. This process is known as nuclear fusion.
109
Explain how nuclear fusion keeps a star stable
State, the effect of fusion has on the main sequence of a star size and the temperature of its core?
That would pressure due to nuclear fusion balances the inward force due to gravitational attraction
It keeps the star is study size and keeps the core hot
110
What are the final stages of the life-cycle start of a super red giant?
Is expands and contracts several times until it finally explodes in a supernova
This leaves behind a very dense cool called a neutron star
Or if the star was massive enough, a black hole
111
Name the force that causes a moon to orbit
What is one similarity and one difference between orbits of the planets and the moon in our solar system
-Gravity
-they both have circular orbits, moons, orbit, planets and planets orbit the Sun
112
Explain what this acceleration changes the planets velocity but not its speed
-planet,, instantaneous velocity and acceleration towards the Sun
-The acceleration at along the radius of the orbit towards the centre
-This means it acts at right angles to the planet speed instantaneous velocity
-acceleration that is perpendicular to the direction of motion does not affect the speed of the motion. It just changes the direction.
-Therefore, the speed of the planet is not changed by the acceleration
-Velocity is a vector quantity with magnitude and direction. The planets velocity is constantly changing because it direction is constantly changing.
-The acceleration course is the planet to move on a circular path. Circular motions means that the object experiences a change in velocity, but not for changing speed.
113
How did the universe start off?
How does the velocity change when something orbits closer?
Hot and dense universe is currently expanding
The closer something is to earth the stronger the gravitational force on the satellite is this means that a larger, instantaneous velocity is needed to balance it, so it would need to or bit faster to remain in the stable orbit
114
two observations that support the idea that the universe is expanding?
Explain why galaxies are not pulled apart by the expansion of the universe ?
Galaxies are moving away from each other,
more distant galaxies are moving away faster
They are, held together by gravity
115
What is meant by Redshift?
The light wavelengths has increased and shifted towards the end of the spectrum - travling away fastest
