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Physics Stage 2 Work Samples Key Concepts covered in Stage 2 Physics: • 2A: Motion and Forces
• Displacement, velocity and acceleration
• Newton’s Laws
• Energy and Power
• 2A: Nuclear Power
• The atom
• Nuclear equations
• Half life
• Energy: E = mc2
• 2B: Electrical Fundamentals
• Static electricity
• Current electricity
• Potential Difference, Resistance and current
• Circuits
• 2B: Heating and Cooling
• Kinetic Theory
• Heat and Temperature
• Specific heat and latent heat
• Heating and cooling in the human body
A Sample Program for a unit in Stage 2 Physics:
Exploring Physics Week Content
Problem Sets Possible Experiments
& Investigations
Assessments
1 1. Describe and explain matter as a collection of
atoms.
1 2. describe and explain the kinetic theory of matter
and apply it to explain properties of matter and changes of state
1‐2 3. distinguish between internal energy, heat and
temperature
E10.2 pg 101
2 4. describe and explain sources of heat, modes of heat
transfer—conduction, convection and radiation and their applications
Set 11 Q. 1,2,4,7,8,9, 16,17
Lab: conduct, convection & radiation e.g.
3
5. describe and explain effects of heat: change in temperature and specific heat capacity—this will
include applying the relationship: TmcQ
Set 12 pg 118 Q. 1,3,4,5,7,8,9, 10,15,17
I 12.2 pg 116
3
6. describe and explain effects of heat: change of state—this will include applying the
relationship: mL Q
Set 13 pg 129 Q.1,2,3,5,9,11,12,16
Optional: E13.1 pg 126 E13.2 pg 127
5 7. method of mixtures – relationships between heat
lost and heat gained in a closed system including phase change
Task 1: Assessing an experiment
6 8. describe and explain effects of heat: thermal
expansion and contraction
Demos: expansion of solids
6 9. describe and explain the conversion of different
forms of energy into heat ‐ energy degradation, and its relationship to conservation of energy
Set 10 pg. 102 Q.2,4,5,6,8,11
Task 5: Assignment Heating
A sample of an assessment program for Stage 2 Physics:
Outcome 01: Investigating and Communicating in Physics; Outcome 02: Energy; Outcome 03: Forces and Fields
Outcomes coverage
Assessm
ent type
Assessm
ent type
weightings
Tasks Content O 1 O 2 O 3
Weighting
Task 1: Assessing an initial Experiment in Motion
Assessing an initial experiment. For example on velocity or acceleration
4
Task 2: Assessing an Experiment in Motion
Assessing an experiment. For example Ep lost = Ek gained
5
Task 3: Assessing an Experiment in Nuclear Physics
Assessing an experiment. For example half‐life
6
Task 4: Assessing an Investigation
Pendulum or other investigation of choice. Should include some errors.
8
Experim
ents and investigations
(35%‐65%)
35%
Task 5: Practical exam (2A) Practical exam on 2A experiments and investigations
12
Task 6: Mini Tests Accumulation of Mini Tests throughout the Semester
5
Task 7: In Class Assignment One Motion and Forces
Assignment One Motion and Forces covers first half of unit.
2
Task 8: In Class Assignment Two Motion and Forces
Assignment Two covers whole Motion and Forces Unit
2
Task 9: Motion and Forces Test Test on Motion and Forces Unit 8
Task 10: In Class Assignment Nuclear Physics
Assignment end of Nuclear Physics Unit
2
Task 11: Test Nuclear Power Test on Nuclear Physics 6
Tests and
Exam
inations
(35%‐65%)
65%
Task 12: 2A Examination Examination on 2A 40
100
In General:
In physics you develop an understanding of the world around you and how it works. This includes the ability to explain the physics involved, both from a practical side and in written answers, to draw and analyse graphs and to carry out calculations involving physics. Each unit in Physics has a workbook which you work through.
Example of a page from the Motion and Forces Workbook
Outcome 3: state, explain and apply Newton's First, Second and Third Laws of Motion‐ this will include applying the relationship: maF resultant
NEWTON’S LAWS OF MOTION
Newton’s First Law of Motion – Inertia
Newton’s First Law of Motion states that a body will not change its state of rest or motion unless acted on by a net external force. This resistance to change is called inertia.
Look at the first two cartoons and discuss how they illustrate Newton’s First Law of Motion.
Now dividually explain how the next four cartoons illustrate Newton’s First Law.
1. Shopping trolley: _________________________________
_______________________________________________
______________________________________________________
2. Pulling tablecloth out from under china:
______________________________________________________
______________________________________________________
NOTE: this can only be done with china not with plastic, why is that so?
_____________________________________________________
_____________________________________________________
Experiments and Investigations: You also conduct investigation. An example is shown below.
Experiment 15.1: Measuring Electrical Energy 1. Purpose: To investigate the relationship between current,
potential difference and electrical energy.
2. Variables: Independent ‐ time adding electrical energy Dependent – change in temperature of water Controls ‐ same current and potential difference
3. Equipment diagram
4. Procedure – read the procedure on page 146.
5. Results table
Measurements Reading
mass of empty calorimeter and accessories
mass of calorimeter and water
Mass of water
initial temperature of water
final temperature
Change in temperature
time of heating
6. Calculations
a. Calculate the electrical energy supplied to the water and calorimeter. E = VIt
b. Calculate the heat energy absorbed by the calorimeter and the water, using their
masses and increases in temperature. Q = mcT
c. Calculate the overall efficiency of the heater in warming the water
100x rcalorimete and waterto suppliedenergy electrical
rcalorimete and by water absorbedenergy heat
7. Discussion. Briefly answer these questions in your lab book.
The amount of electrical energy put into the water should equal the amount of energy absorbed to heat the calorimeter and the water. a. Compare and discuss the two values calculated above and account for any discrepancies. b. Discuss the efficiency of the system in heating the water
Tests and Examinations
Tests and examinations form a reasonable proportion of physics assessments. Below are some examples of the types of questions you will need to answer as well as their answers.
Written Type Question:
Easy recall
Non‐physics people often use the word heat when then actually mean temperature or even internal energy (thermal energy) of the object. Explain the difference between the three (words in italics).
(3 marks) Heat is the transfer of energy from an object at a higher temperature to one at a lower
temperature until thermal equilibrium is reached. Temperature is a measure of the average kinetic energy of an object. Thermal or Internal energy is the sum of the kinetic and potential energy of an object.
Harder (using your understanding of physics to explain a situation)
Explain why you feel yourself being pushed back into your seat when sitting in your car when it first accelerates. (3 marks)
• Newton’s first Law states that “Things like to keep doing what they are doing unless acted on by a net external force”.
• Therefore when a car accelerates and moves forward the occupants are pushed back in their seats
• because they tend to remain what “they were doing” which was being still.
Mathematical Type Questions:
Simple
A spark of 2.00 x 10‐9 C jumps between two charged particles. If the spark lasts for 1.00 s calculate the current that flows during this time? (2 marks)
6
9
10x0.1
10x2
t
qI
q = 2.00 x 10‐9 C t = 1.0 x 10‐6 I = 2.00 x 10‐3 A (3 sf) Harder Shane is on a sightseeing tour in a helicopter. When the helicopter is travelling downwards at 5.00 m s‐1, Shane looks out of the window and his 0.100 kg sunglasses fall off. If the glasses were 145 m above the ground when they fell off, with what velocity will the sunglasses hit the ground? (2 marks)
v2 = u2 + 2gs u = 5.0 ms‐1 = (52) + (2 x 9.8 x 145) [1 mark] v = ? = 25 + 2842 m = 0.10 kg = 2867 = 53.544 s = 145 m v = 53.5 m s‐1 [1 mark] g =9.8 ms‐2
Drawings and Graphs:
Easy recall
Draw the field around the following TWO situations. (4 marks)
a. b. Harder (applying physics understanding or interpret a graph)
Look at the following graph.
Calculate the displacement of the object. (3 marks)
displacement is area under the graph: Area A = ½ x 30 x 6 = 90 Area B = 10 x 6 = 60 Area C = ½ x 20 x 6 = 60 displacement = 210 s = 2.10 x 102 m
Physics Stage 3 Work Samples
Key Concepts covered in Stage 3 Physics: • 3A: Motion and Forces
• Vector components
• Projectiles
• Circular motion
• Gravitational Motion
• 3A: Electromagnetism
• Magnets
• Electromagnetism
• Motors, generators and transformers
• 3B: Particles, Waves and Quanta
• Waves and Sound
• Atomic Phyiscs
• Frames of Reference and Relativity
• 3B: Motion and forces in electric and magnetic fields
• Electric fields
• Forces on charged particles
A Sample Program for a unit in Stage 3 Physics:
Exploring Physics
Week Content
Physics Content & Contexts 3A
& 3B
Possible Problem Sets
Possible Experiments & Investigations
Assessments
1‐2
Motion and forces in electric and magnetic fields 1. explain that point charges create radial
electric fields 2. describe, using diagrams, electric field
distributions around simple combinations of charged points, spheres and plates
3. describe, explain and use electric fields between parallel plates and within uniform conductors, to explain the forces on charged particles—this will include applying the
relationships: d
V
q
FE
Unit 2A & 2B text Pg. 334‐346
Set 14: Charged Particles in Magnetic Fields
3‐4
4. apply the concept of force on a charged particle moving through a magnetic field—this will include applying the relationships:
r
mvF ,qvBF
2
5. describe the factors which affect the magnitude and direction of the force on a charged particle moving through a magnetic field
Pg. 347‐364 Expt: 14.1 Task 3: Extended Investigation due Task 5: Validation tests on homework and assign.
6‐7
6. explain and apply the concepts of electric and magnetic field in sequence or in combination—this will include applying the relationships:
r
mvF ,qvBF ,
d
V
q
FE
2
Pg. 347‐364 Set 15: Charged Particles in fields
Expt: 15.1 Task 10: Test Motion and Forces in electric and magnetic fields
A Sample Program for Stage 3 Physics: Assessment outline: Stage 3 PHYSICS
Outcome 01: Investigating and Communicating in Physics; Outcome 02: Energy; Outcome 03: Forces and Fields
Outcomes coverage
Weighting %
Assessm
ent type
Assessm
ent type
weightings
Tasks Content 1 2 3 3A 3B Total
Task 1: Practical exam (3A) Practical exam on 3A experiments and investigations
7 7
Task 2: Independent Investigation
Independent investigation (2% planning; 4% final report)
2 4 6
Experim
ents and
investigations
(20‐40%)
20%
Task 3: Practical exam (3B) Practical exam on 3B experiments and investigations
7 7
Task 4:Regular mini tests Accumulation of mini tests on homework and course content
2 2 4
Task 5: Test ONE Motion and Forces in Gravitational Fields
Test up to and including projectile motion
3 3
Task 6: Test TWO Motion and Forces in a Gravitational Field
Test for whole unit with focus on concepts after projectile motion.
5 5
Task 7: Test electricity and magnetism
Test on Electricity and Magnetism unit
6 6
Task 8: Test ONE Particles, waves and quanta
Test on Waves and Sound 4 4
Task 9: Test TWO Particles, waves and quanta
Test on Atomic Physics, Astrophysics and Relativity
4 4
Task 10: Test Motion and Forces in Electric and Magnetic Field
Test on Motion and Forces in Electric and Magnetic Field unit
4 4
Task 11: Semester One Examination
Examination on 3A 15 15
Tests
and
Exam
inations
(60‐80%)
80%
Task 12:Stage 3 Examination (includes 29% of 3A) (Need to buy WATP)
Examination on Stage 3 work 10 25 35
50 50
Total 100
100
In General: In physics you develop an understanding of the world around you and how it works. This includes the ability to explain the physics involved, both from a practical side and in written answers, to draw and analyse graphs and to carry out calculations involving physics. Each unit in Physics has a workbook which you work through.
Example of a page from the Motion and Forces Workbook
Outcome 9: explain and apply Newton's Law of Universal Gravitation and the concept of gravitational acceleration, g, as gravitational field strength—this will include applying the relationships:
2221
gr
MGg ,
r
mmGF
Gravitation Fields and Universal Gravitation
Consider a tower several miles high with a horizontal canon on top. The velocity at which the cannon ball is fired is increased every time.
Each time it falls back to the ground except the last time where it keeps falling towards the Earth but the Earth curves away from it as it falls. It is in orbit.
All satellites, both artificial and natural, are in free fall and their acceleration depends only on where they are. Close to Earth the acceleration is 9.8 m s‐2. In much higher orbits they move slower and have a lower acceleration.
Gravitational Fields Text Reference pg. 54‐62
Newton’s talent for clear thinking provided most of the logical framework for our modern understanding of motion of everyday objects. He explained the forces which attract falling objects towards the Earth and why satellites stay in orbit. He found that all object attract each other with a force which is proportional to the product of their masses and inversely proportional to the square of their distance apart.
So 2
21g
r
mmF
This is known as Newton’s Law of Universal Gravitation.
To turn a proportionality into an equation you need to add a constant, in this case, G – the gravitational constant. where Fg = force in newtons (N) m1 & m2 = masses of objects (kg) 2
1g
mmG 2
rF
r = distance apart (m) G = gravitational constant, 6.67 x 10‐11 N m2 kg‐2
Your teacher will work through the following examples with you.
Helpful hint: A common error for students is to forget to square the radius.
Example: The mass of the Earth is 6.00 x 1024 kg. If the centres of the Earth and moon are 3.90 x 108 m apart, the gravitational force between them is about 1.90 x 1020 N. What is the approximate mass of the moon?
Experiments and Investigations: You also conduct investigation. An example is shown below. Once this experiment was carried out, written up and discussed, a validation test was conducted on it.
Purpose: To show that a single force can be resolved into components at right angles to one another
Background Information: In this experiment, you will compare the theoretical value of the vertical and horizontal components of the
tension (T) with your recorded values. The vertical component (Tv = T sin ) should be the same as the weight (W)
and your horizontal component (Th = T cos ) should be the same as the thrust (T) below.
Note: Ensure the dowel is level by using a spirit level.
Equipment: Set‐up as shown in diagram:
Procedure: 1. Set up the equipment as shown. 2. Add 500 g slotted masses as weight.
Record the weight (W) in the table below for trial one.
3. With the dowel horizontal, adjust the equipment until an angle between
400 and 650 is obtained for . Measure and record for trial one.
4. Gently pull on the thrust (P) spring balance horizontally until the nail just moves away from the wood supporting it. Record the thrust (P).
5. Without moving the thrust, record the tension (T) on the tension spring balance.
6. Repeat the experiment for two other angles of within 400 and 650 everything else remains the same.
Results: Trial 1 Trial 2 Trial 3 Angle
Weight (W)
Thrust (P)
Tension (T)
Trial 1 Trial 2 Trial 3
Vertical component of tension (Tv = T sin )
Horizontal component of tension (Th = T cos )
Difference between Tv and W
Difference between Th and P
Calculations and Questions to Answer:
1. When the angle is made smaller, what happens to the tension (in string) and the thrust on the boom?
2. The weight of the beam in this experiment was ignored. Is this reasonable? If so, why? 3. Express the average difference between Tv and W as a percentage of W. Do the same for Th and P
compared to P. Are these errors acceptable?
Discussion: Write a general discussion on your investigation and relate the vector to its components both theoretically and experimentally. Evaluation: Discuss your sources of error and how the experiment could be improved.
Tests and Examinations Tests and examinations form a reasonable proportion of physics assessments. Below are some examples of the types of questions you will need to answer as well as their answers.
Written Type Question: Easy recall
Pylons supporting high voltage (e.g. 500 kV) transmission cables tend to be very high and located away from populated areas. Give two reasons why electrical power is transmitted at very high voltages such as 500 kV? (3 marks) 1. Plost = I
2R. Reduce current means reduces power lost as heat
2. As P = VI, if V is very large the current is small. Small current needs much thinner wires to transport so much cheaper.
Harder (using your understanding of physics to explain a situation) A transformer is being tested. The primary coil is connected to a battery and a switch. The switch is closed allowing current to flow to the primary coil. An ammeter is connected to the secondary coil and initially deflects to the right then returns to its normal position.
a. Name the Law and explain why the meter needle deflected when the switch is initially closed.
(4 mark)
Faraday’s Law When switch is closed, the current starts (increases). Changing current produces a changing magnetic field in the primary coil. This induces an emf in the secondary coil – Faraday’s Law An induced emf will create an induced current which in turn causes the meter needle to deflect. NOTE 1: As there is a complete circuit, then an electron current is induced NOT Eddy Currents. Eddy Currents are only for pieces of metal that are not part of a full circuit. NOTE 2: Lenz’s Law explains that the induced current is in the opposite direction to the primary current but question doesn’t ask this so not required.
Mathematical Type Questions: Simple A 100.0 g ball is attached to a 20.0 cm string. It is swung in a horizontal circle. If the string can withstand a tension of 30.0 N before it breaks, what is the maximum speed the ball can have?
(3 marks)
m = 0.10 kg r = 0.20 m F = 30.0 N [1 mark] [1 mark]
601.0
20.0x30v
20.0
xv1.030
r
mvF
2
2
2
v = 7.75 m s‐1 [1 mark[
Harder 1. A crane lifts 6.00 x 102 kg load of rubble on a building
site. The 7.00 m crane arm is uniform and has a mass of 2.80 x 102 kg. The cable used to raise and lower the load is attached to the crane arm 5.00 m along the arm. Calculate the tension in the cable. (4 marks)
Take moments about B
CM = ACM (5880 x 5.734) + 2744 x 2.867) = 1.710T [3 marks] 33715.92 + 7867.048 = 1.71T 41582.968 = 1.71 T T = 24318 N T = 2.43 x 104 N [1 mark]
r1 = 3.5 cos 35 = 2.867 m r2 = 7 cos 35 = 5.734 m r3 = 5 sin 20 = 1.710 m
Drawings and Graphs:
Easy recall
You are doing a movie stunt. You have to leap from one roof to another 2.50 m away. There is a drop of 50.0 m if you fail (splat!!). You take a long run up and upon a signal from the director you leap over the gap. Halfway across you happen to glance down. Draw a free body diagram showing any forces acting on you at that moment including label. (By the way, you do land safely on the other side.) (2 marks)
One you leave the building, the only force acting on you (assuming no air resistance) is gravity. [1 mark arrow, 1 mark label]
Harder (applying physics understanding or interpret a graph)
This is from a semester examination.
Section Three: Comprehension 20% (36 Marks)
This section contains two (2) questions. You must answer both questions. Write your answers in the space provided.
Question 22: (18 marks)
A teacher set up a demonstration to show the force exerted on a current carrying conductor by another current carrying conductor as the current flow is varied in each conductor. The circuit diagram the teacher sets up is shown to the right. The teacher was able to measure the force wire B exerts on wire A by using a data logger attached to a computer. Resistance in the wires is negligible. The teacher fixed the distance between the two wires to be 0.0100 m and the lengths of wires A and B to be 0.200 m. The relationship the teacher was investigating can be found from the following formula:
where: F is the force of wire B on wire A (N)
d2
IIF 21o
l is length of wires (m) l
o is the permeability of free space I1 and I2 are the currents flowing in the wires (A) d is the distance between the wires (m)
a. List the variables for this experiment. (4 marks) Independent variable: size of current (1 mark) Dependent variable: force (1 mark) Control variables: thickness of wires same material for wires length of wires (two suitable answers – 2 marks)
The results of the demonstration are shown in the table below:
IA IB F (x 10‐7) IA x IB
1.00 1.00 3.94 1.00
2.00 2.00 16.01 4.00
3.00 3.00 36.10 9.00
4.00 4.00 63.93 16.0
5.00 5.00 99.97 25.0
6.00 6.00 144.03 36.0
(1 mark) b. Complete the last column of the table. (1 mark)
c. On the graph paper on the next page, plot the graph of force vs (IA x IB). (5 marks)
d. State the relationship between the force exerted by wire B on A and the current flowing in the wires. (2 marks)
It is a linear relationship (1 mark) F being proportional to (IA x IB) (1 mark)
e. Calculate the gradient of the line of the graph including units to the correct number of significant
figures. (3 marks) Student should indicate on graph where they took the gradient from, if not, deduct 1 mark
as per graph, gradient = 20
10x80 7
(1 mark)
= 4.0 x 10‐7 N A‐2 NB: should only be 2 significant figures, (1 mark) (1 mark) if not, deduct 1 mark
f. Using your gradient and the formula, calculate the value of 0 including units. (3 marks)
d2
IIF 21o
l
so BAxII
F =
d20l but
BAxII
F = gradient
so 4.00 x 10‐7 =
d20l (1 mark)
4.00 x 10‐7 =
01.02
20.00
o = 2.0
01.0xx2x10x00.4 7
units: xmA
Nxm2
o = 1.3 x 10‐7 N A‐2 NB: only 2 significant figures, if not, deduct
(1 mark) (1 mark) 1 mark