Paper 1 Content Flashcards
1
Q
Base units
A
m ,kg, s, A, K, mol
2
Q
Prefix order (descending)
A
Tera, Giga, Mega, kilo, centi, milli, micro, nano, pico, femto
3
Q
Scalar quantity definition
A
A quantity with magnitude but no direction
4
Q
Scalar quantity examples
A
Mass (kg), speed (ms^-1), p.d. (V), energy (kgm^2s^-2)
5
Q
Vector quantity definition
A
A quantity with both magnitude and direction
6
Q
Vector quantity examples
A
Displacement (m), velocity (ms^-1), force (N), acceleration (ms^-2), momentum (kgms^-1)
7
Q
How to find the direction of a perpendicular vector
A
Find the angle between the between the horizontal and diagonal line using trig^-1
8
Q
What does the gradient of a distance-time graph represent
A
Speed
9
Q
Instantaneous speed definition and how to find it on a graph
A
The speed of a car over a very short time interval. Found by drawing a tangent at one point on a distance-time graph.
10
Q
How do you find the velocity from a distance time graph
A
The gradient of the graph section. Using a tangent if it is a curved section
11
Q
How to find acceleration and displacement from a velocity-time graph
A
The gradient of a v-t graph is acceleration, using a tangent at a point if curved. Displacement can be found by finding the area under the graph.
12
Q
what will a velocity time graph look like with different acceleration types
A
The graph will be a straight, diagonal, line for constant acceleration or deceleration, a flat line for no acceleration and a curve for changing acceleration.
13
Q
Stopping distance definition
A
Thinking distance + braking distance
14
Q
Thinking distance definition
A
The distance traveled between when it’s first noticed that there’s a reason to stop and when they start braking.
15
Q
Braking distance definition
A
The distance travelled from when the brake is first applied until the vehicle fully stops
16
Q
How to find thinking distance
A
Speed of the vehicle x reaction time
17
Q
Experiment to find gravity
A
-hold a ball at a measured height above the ground using a clamp
-place two light gates below this with a measured distance between them
-release the ball from the clamp
-it will interrupt the light gates as it falls starting the timer at the first and ending it at the second
-plot a graph of distance against time^2 and find the gradient and x2 as s=1/2gt^2
18
Q
In projectile motion what is the general acceleration horizontally or vertically? What does this mean for the velocity?
A
Horizontal acceleration: 0
Vertical acceleration: 9.81 or -9.81
Horizontal velocity (u and v): remains constant
Vertical velocity (u and v): changes
19
Q
difference between energy and work done
A
Work is the transfer of energy when a force moves something. energy is the capacity to do work. (movement is required for work to be done)
20
Q
How to find the weight of an object in a lab
A
Using a newtonmeter or w=mg
21
Q
What is a centre of mass
A
A point on an object through which an external force produces motion but no rotation. It is a point where the entire weight of the object appears to act.
22
Q
How to find the centre of mass/gravity in a lab
A
It can be found as it is vertical below the point of suspension when the object if lifted. Create holes around the objects edge and hang it, draw vertical lines downwards from this point and repeat for other holes. Where the lines cross is the centre of mass
23
Q
How to find normal contact force of an object on a slope
A
-weight acts vertically downwards
-mgcos(x) can be used to find the force opposing the normal contact force (x is the angle between the slope and the horizontal)
-this is equal to the normal contact force
24
Q
What is drag
A
The frictional force acting on an object that opposes the motion of the object
25
Terminal velocity definition
When the drag of an object in motion is equal to the weight of the object. Acceleration is 0.
26
How does terminal velocity occur
-the object initially releases with no air resistance and is only acted on by weight. acceleration=9.81
-The drag of the falling object increases as the speed increases.
-The resultant force decreases.
-instantaneous acceleration becomes less than gravity
-The resultant force becomes 0 and acceleration now=0
27
How to show terminal velocity in a lab
-measure and record the mass (using a digital balance) and diameter (at 3 different places) of a metal ball
-drop the ball in a measuring cylinder full of a viscous liquid
-measure the time taken for the ball to sink to the bottom
-divide this time by 6 and drop the ball again marking where it reaches every 1/6 of the time it took to sink with a pen
-measure the displacements between each of these points with a ruler
-draw a displacement-time graph and see if it looks like it’s reached terminal velocity
28
Definition of a moment
The force on an object multiplied by the perpendicular distance of this force from the pivot
29
Principle of moments
For an object in rotational equilibrium, the sum of the clockwise moment = sum of the anticlockwise moment.
30
Torque definition for a couple
One of the forces in the couple multiplied by the perpendicular distance between the forces
31
Forces in equilibrium meaning
Net force and net moment acting on the object are both 0
32
How to show forces in equilibrium
A closed triangle with arrows going head to tail in a loop.
33
Density definition
The mass per unit volume of a substance
34
How to find density of a liquid in a lab
For liquids: find the volume from a measuring cylinder and mass from a digital balance
35
How to find density of an irregular solid in a lab
The volume can be found using the displacement of a liquid after putting the solid in it. It is the difference between the water levels before and after it is dropped in it using a measuring cylinder. Measure mass on a digital balance.
36
How to find the density of a regular solid in a lab
measure all three dimensions of the object using a ruler calliper or micrometer and multiply them for volume. Use a digital balance for the mass
37
What is special about pressure in a fluid
It acts in all directions
38
What is archimedes principle
The upthrust on a body in a fluid is equal to the weight of the fluid the body displaces
39
Why do some objects in a fluid float?
Their weight must be equal to the weight of the fluid displaced.
40
Light object such as wood is submerged in water. What happens?
-upthrust and weight immediately act on the object
-upthrust is greater than weight and weight is less than the weight of displaced water causing it to accelerate upward
-it exits at the waters surface
-weight and upthrust are now in equilibrium, less water is displaced
41
Newton’s first law definition
An object at rest or moving with constant velocity will remain that way unless acted on by a resultant force
42
How can you reduce random errors
Repeat the experiment many times
43
How do you find the combined uncertainty quantities being added or subtracted
always ADD the absolute uncertainties
44
How do you find the combined uncertainty quantities being multiplied or divided
Add the percentage uncertainties
45
How do you find the combined uncertainty quantities raised to a power
Multiply the percentage uncertainty by the power
46
How do you convert from absolute to percentage uncertainties
To find the percentage uncertainty: divide the absolute uncertainty by the measured value and x100
To find the absolute uncertainty:
Divide the percentage uncertainty by 100 and multiply by the measured value
47
How do you show uncertainties on a graph
Draw error bars at the measured points
48
How do you find the uncertainty using error bars on a graph
Top left to bottom right or top right to bottom left of the error bars draw a line of worst fit. The gradient of this is used to show the maximum possible error in the gradient of the data.
49
Newton’s third law definition
When two objects interact, they exert equal and opposite forces on eachother
50
What are the conditions for Newton’s third law to apply
-the forces must be of the same type
-they must act on two different objects
51
What is the resultant force on an object travelling at a constant velocity
0N
52
conservation of energy definition
the total energy in a closed system remains constant as energy cannot be created or destroyed but can only be transferred.
53
internal energy definition
the sum of the random kinetic energy and the random potential energy of atoms in a system
54
elastic deformation definition
a reversible change in the shape of an object due to a compressive or tensile force. when the force is removed it will return to its original shape
55
plastic deformation
an irreversible change to the shape of an object due to tensile or compressive forces. when the force is removed it will not return to its original shape.
56
hookes law
the extension on a spring is directly proportional to the force applied to it provided the limit of proportionality has not been exeeded.
57
how to show hookes law in a lab
-attach a spring to the end of a clamp suspended on a stand above a bench
-place a metre rule next to the spring
-add masses to the spring and check the extension for each mass added
-wear goggles and have it at eye level to reduce parallax error
-repeat experiment 3+ times
-plot F (mass x 9.81) against extension on graph
-hookes law is shown if line of best fit is proportional through 0
58
limit of proportionality definition
the force beyond which stress is directly proportional to strain
59
elastic limit definition
the force beyond which the material will no longer return to its original shape and will deform plastically.
60
what is the area under a force-extension graph equal to
work done
61
what happens to work done in plastic vs elastic deformation
elastic: the elastic potential energy is fully recoverable
plastic: energy has gone into moving atoms into new permanent positions so this part is not recoverable
62
what does a force-extension graph look like for a spring. draw it
look it up
63
what does a force-extension graph look like for rubber bands. draw it
look it up.
64
what does a force-extension graph look like for polythene strips. draw it
look it up
65
what is the area inside the hysteresis loop of a rubber force-extension graph equal to
the thermal energy released when the rubber is loaded and unloaded
66
what are yield points on a stress-strain graph
where the material extends rapidly
67
what does a stress-strain graph look like for a brittle material. draw it
a directly proportional line which does not curve at the top but abruptly stops (when it snaps)
68
what is the ultimate tensile strength of a material and what happens after this
the maximum stress a meterial can be stretched before it breaks after which it will become longer and thinner and snaps at its breaking point.
69
draw a stress-strain graph for a metal (ductile) and label: the limit of proportionality, elastic limit, yield points, ultimate tensile strength and breaking point
look it up
70
how to find young modulus on a stress-strain graph
the gradient of the linear region
71
stiffness definition
the ability of an object to resist deformation
72
how to compare the stiffness of objects
compare the young modulus. bigger young modulus=stiffer
73
how to find young modulus in a lab
-measure the initial length of a metal wire with a meter ruler and its diameter using a micrometer at at least 3 different points along it to find an average
-use this to find its cross sectional area
-clamp the wire to one side of a bench and put the other side over a pulley at the opposite end with a marked point on the wire above a ruler and note this point
-place known masses at the end of the wire
-each time analyse the distance the marked point has moved (extension)
-calculate the stress and strain of the wire
-plot a stress-strain graph and find the gradient of the straight part for the young modulus
74
draw a stress-strain graph of a polymer
look it up
75
what is the law of conservation of momentum
total momentum of a system remains the same before and after a collision provided no external forces act on the system
76
what happens when two objects collide
-some momentum is transferred from one object to the other
-some kinetic energy is transferred from one object to the other
-total momentum does not change
77
what is a closed system
an isolated system which has no interaction with outside influences or forces.
78
how to show momentum of a collision in a lab
-place a meter ruler next to a linear track
-find the masses of two trolleys with a digital balance
-place two trolleys (with magnets facing eachother if inelastic)on the linear track. one at 0m and one at 0.5m
-push one trolley so that it collides with the second
-time how long it takes to reach the second trolley at 0.5m and then how long it takes for the combined trolleys to reach 1m
-use this to find the velocity before and after the collision
-repeat for means
-use p=mv to find momentum before and after
79
what is conserved in a perfectly elastic collision
everything is conserved:
-momentum
-total energy
-total kinetic energy
80
what is/isn't conserved in an inelastic collision
-momentum
-total energy
-not total kinetic energy
81
newtons second law definition
the resultant force acting on an object is directly proportional to the rate of change of momentum and acts in the same direction
82
when can F=ma be used instead of newtons 2nd law
when the mass of the object is constant
83
impulse definition and equation
the product of the force and the time for which the force acts. Force x Δtime =Δmomentum
84
how do you find the impulse from a force-time graph
the area underneath it
85
how to resolve momentum
initial momentum in x direction=final momentum in x direction
initial momentum in y direction=final momentum in y direction
resolve the same way as any other vector
86
What are the conditions for an object to be in equilibrium
-resultant force must =0
-resultant moment must =0
87
What error is caused by looking at an experiment from the wrong angle? How to solve this?
Parallax error. Have the experiment at eye level
88
What is the triple point of a substance
A temperature and pressure where the three phases of matter can exist in thermal equilibrium.
89
Thermal equilibrium definition
When two objects have no net flow of thermal energy between them.
90
What does it mean for two objects to be in thermal equilibrium
They must be the same temperature
91
What is a zero-error
When measuring something, the equipment shows a non-zero reading when in reality it should be zero
92
Precision vs accuracy
Accuracy: how close a measurement is to its true, accepted value
Precision: how close a set of measurements are to eachother
93
How convert from Celsius to kelvin
+273 to the Celsius number it will always be a positive number in kelvin
94
Absolute zero definition
The lowest possible temperature at which the substance has minimal internal energy
95
When to use degrees vs when to use kelvin
always use kelvin when temp is shown as T. use either degrees or kelvin for θ (based on whats given in the question)
96
what is the structure of solids in terms of spacing, ordering and motion of atoms
-arranged in a uniform structure with strong electrostatic of attraction between atoms
-fixed position but can vibrate (more vibration if heated) and therefore have kinetic energy
-atoms are close together
97
what is the structure of liquids in terms of spacing, ordering and motion of atoms
-particles are free to move non-uniformly around eachother without a fixed shape
-more kinetic energy than solids
-still electrostatic forces between the atoms so still close together
98
what is the structure of gases in terms of spacing, ordering and motion of atoms
-atoms are far apart as there is almost no attraction
-move freely and non uniformly at high speeds
-no fixed shape
99
what is it called when a solid changes state to a liquid
melting
100
what is it called when a liquid changes state to a gas
boiling/evaporation
101
what is it called when a gas changes state to a liquid
condensation
102
what is it called when a liquid changes state to a solid
freezing
103
what is the kinetic model
104
what is Brownian motion
the continuous random motion of particles in a fluid (liquid or gas)
105
how is brownian motion shown in a lab
-fill a smoke cell with smoke particles by burning paper
-seal the cell to stop these particles escaping
-shine a bright light through the smoke cell after turning off main lights
-look through a microscope at the centre of the smoke cell
-tiny bright dots (smoke cells) will be seen jittering randomly
-this is because of their collisions with tiny air particles
106
what happens when the temperature of a substance is increased in terms of internal energy, KE and PE
-internal energy increases
-average kinetic energy of the atoms increases
-potential energy of the atoms remain the same
107
what happens when a substance changes phase in terms of temp, internal energy, KE and PE
-temp doesn't change
-kinetic energy doesn't change
-potential energy significantly increases
-internal energy increases
108
draw a graph for a solid being heated up until it becomes a gas and label where: KE changes, PE changes, the states of matter, the processes of the changes of state, the axis, internal energy
-temp on y-axis time on x-axis
-directly proportional line from 0 for solid where KE and temp increases but PE remains the same
-flat section where PE increases but temp and KE are the same (melting->, freezing<-)
-proportional line for liquid where KE and temp increases but PE remains the same
-flat section where PE increases but temp and KE are the same (boiling->, condensation <-)
-proportional line for gas where KE and temp increases but PE remains the same
-internal energy increases throughout
109
specific heat capacity definition
the energy required to change the temperature of 1kg of a substance by 1K
110
how to find the specific heat capacity of a solid in a lab
-find the mass of a solid using a digital balance with holes for a thermometer and electric heater
-place the solid in an insulating substance
-measure the current and p.d of the heater by connecting it to an ammeter and voltmeter
-set a timer for 10 minutes
-check the temp before and after the 10 mins on the thermometer by looking at eye level to reduce parallax error
-c = IVt/mΔθ
111
how to find the specific heat capacity of a liquid in a lab
-find the mass of a liquid using a digital balance
-pour the liquid in an insulating container
-place a thermometer in the liquid and measure the initial temp (at eye level to reduce parallax error)
-place an electric heater connected to a voltmeter and ammeter in the liquid
-time this for 10 mins whilst stirring to uniformly distribute the heat
-after 10 mins find the final temp on the thermometer
-c = IVt/mΔθ
112
what is the method of mixtures and what is needed
a way to find the specific heat capacity of a substance by mixing two substances at different temperatures: requires both known masses, the final temperature (when they are in thermal equilibrium), specific heat capacity of one of the substances.
113
specific latent heat definition
the energy required to change the phase of a substance per 1kg whilst at a constant temperature
114
how do you find the specific latent heat of fusion in a lab
115
how do you find the specific latent heat of vaporisation in a lab
116
what assumptions are made in the kinetic model for an ideal gas
-the atoms occupy a negligible volume compared to the volume of the gas
-atoms in the gas move in random directions at random speeds
-the collisions of particles with eachother and the container walls are perfectly elastic
-the time of collisions between atoms is negligible compared to collisions with the walls
117
how does the kinetic model of an ideal gas show newtons laws
-when atoms collide with the container wall, they exert a force on the wall which exerts an equal and opposite force on them (3rd law)
-this changes their momentum as they bounce off as a force is exerted over a short length of time (2nd law)
-this changes the atoms direction making its velocity change from 2mu to -2mu
-the atom travels to and collides with the other wall and repeats this
-as the atom collides with the wall, it causes pressure on the wall as P=F/A
118
Boyles law definition
the pressure of an ideal gas is inversely proportional to its volume provided that the mass of the gas and its temperature do not vary
P∝ 1/V
119
experiment to show boyles law in a lab
120
Charles law definition
for a constant pressure, the volume of a gas is directly proportional to the temperature.
V∝T
121
what is the relationship between pressure and temperature. what are the conditions for this?
provided that the volume and mass of the gas remains constant, pressure is directly proportional to temperature.
p∝T
122
what is absolute zero in kelvin
0K
123
what is absolute zero in celcius
-273°C
124
how do you estimate absolute zero in a lab
-place a water bath on a an electric heater and a thermometer in the water
-fill a flask with dry air, seal it and attach a pressure gauge
-watch the thermometer and pressure gauge as the water is heated at eye level to reduce parallax error
-plot a graph of temp against pressure and extrapolate to find absolute 0
125
draw and label a maxwell-boltzmann distribution. where is the most probable speed, mean speed, root mean square speed, axis and temperature of 2 curves
look it up
126
127
how to calculate root mean square speed
square each speed and add each speed, ignoring any negative signs (as it is a scalar) then divide by the number of of numbers. then root this
