Exploring Physics Possible Experiments & Investigations

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1 Physics Stage Work Samples Key Concepts covered in Stage Physics: A: Motion and Forces Displacement, velocity and acceleration Newton s Laws Energy and Power A: Nuclear Power The atom Nuclear equations Half life Energy: E = mc B: Electrical Fundamentals Static electricity Current electricity Potential Difference, Resistance and current Circuits B: 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 Physics: Week Content 1. Describe and explain matter as a collection of atoms.. describe and explain the kinetic theory of matter and apply it to explain properties of matter and changes of state 3. distinguish between internal energy, heat and temperature 4. describe and explain sources of heat, modes of heat transfer conduction, convection and radiation and their applications 5. describe and explain effects of heat: change in temperature and specific heat capacity this will include applying the relationship: Q mct 6. describe and explain effects of heat: change of state this will include applying the relationship: Q ml 7. method of mixtures relationships between heat lost and heat gained in a closed system including phase change 8. describe and explain effects of heat: thermal expansion and contraction Problem Sets Set 11 Q. 1,,4,7,8,9, 16,17 Set 1 pg 118 Q. 1,3,4,5,7,8,9, 10,15,17 Set 13 pg 19 Q.1,,3,5,9,11,1,16 Exploring Physics Possible Experiments & Investigations E10. pg 101 Lab: conduct, convection & radiation e.g. I 1. pg 116 Optional: E13.1 pg 16 E13. pg 17 Demos: expansion of solids Assessments Task 1: Assessing an experiment

2 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. 10 Q.,4,5,6,8,11 A sample of an assessment program for Stage Physics: Task 5: Assignment Heating Outcome 01: Investigating and Communicating in Physics; Outcome 0: Energy; Outcome 03: Forces and Fields Assessment type Assessment type weightings Tasks Content Outcomes coverage O 1 O O 3 Weighting Task 1: Assessing an initial Experiment in Motion Assessing an initial experiment. For example on velocity or acceleration 4 Experiments and investigations (35% 65%) 35% Task : Assessing an Experiment in Motion Task 3: Assessing an Experiment in Nuclear Physics Task 4: Assessing an Investigation Assessing an experiment. For example E p lost = E k gained Assessing an experiment. For example half life Pendulum or other investigation of choice. Should include some errors Task 5: Practical exam (A) Practical exam on A experiments and investigations 1 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. Task 8: In Class Assignment Two Motion and Forces Assignment Two covers whole Motion and Forces Unit Tests and Examinations (35% 65%) 65% 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 Task 11: Test Nuclear Power Test on Nuclear Physics 6 Task 1: A Examination Examination on A

3 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: resultant F ma 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:. Pulling tablecloth out from under china: NOTE: this can only be done with china not with plastic, why is that so?

4 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.. 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 Results table Measurements 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 Reading 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 heat energy absorbed by water and calorimeter electrical energy supplied to water and calorimeter x 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

5 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.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? ( marks) q =.00 x 10 9 C t = 1.0 x 10 6 I q t x10 1.0x Harder I =.00 x 10 3 A (3 sf) 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 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? ( marks) v = u + gs u = 5.0 ms 1 = (5 ) + ( x 9.8 x 145) [1 mark] v =? = m = 0.10 kg = 867 = s = 145 m v = 53.5 m s 1 [1 mark] g =9.8 ms

6 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. displacement is area under the graph: Area A = ½ x 30 x 6 = 90 Area B = 10 x 6 = 60 Area C = ½ x 0 x 6 = 60 (3 marks) displacement = 10 s =.10 x 10 m

7 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: Week Content Motion and forces in electric and magnetic fields 1. explain that point charges create radial electric fields. 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 F V relationships: E q d 4. apply the concept of force on a charged particle moving through a magnetic field this will include applying the relationships: mv F qvb, F r 5. describe the factors which affect the magnitude and direction of the force on a charged particle moving through a magnetic field Physics Content & Contexts 3A & 3B Unit A & B text Pg Possible Problem Sets Set 14: Charged Particles in Magnetic Fields Exploring Physics Possible Experiments & Investigations Assessments Pg Expt: 14.1 Task 3: Extended Investigation due Task 5: Validation tests on homework and assign.

8 explain and apply the concepts of electric and magnetic field in sequence or in combination this will include applying the relationships: E F q V d, F qvb, mv F r A Sample Program for Stage 3 Physics: Pg Set 15: Charged Particles in fields Expt: 15.1 Task 10: Test Motion and Forces in electric and magnetic fields Assessment outline: Stage 3 PHYSICS Outcome 01: Investigating and Communicating in Physics; Outcome 0: Energy; Outcome 03: Forces and Fields Assessment type Assessment type weightings Tasks Content Outcomes coverage Weighting % 1 3 3A 3B Total Experiments and investigations (0 40%) Tests and Examinations (60 80%) 0% 80% Task 1: Practical exam (3A) Task : Independent Investigation Task 3: Practical exam (3B) Task 4:Regular mini tests Task 5: Test ONE Motion and Forces in Gravitational Fields Task 6: Test TWO Motion and Forces in a Gravitational Field Practical exam on 3A experiments and investigations Independent investigation (% planning; 4% final report) Practical exam on 3B experiments and investigations Accumulation of mini tests on homework and course content Test up to and including projectile motion Test for whole unit with focus on concepts after projectile motion. Test on Electricity and Magnetism unit Task 7: Test electricity and magnetism 6 6 Task 8: Test ONE Particles, waves and quanta Test on Waves and Sound 4 4 Task 9: Test TWO Particles, Test on Atomic Physics, waves and quanta Astrophysics and Relativity 4 4 Task 10: Test Motion and Test on Motion and Forces in Forces in Electric and Magnetic Electric and Magnetic Field unit Field 4 4 Task 11: Semester One Examination Examination on 3A Task 1:Stage 3 Examination (includes 9% of 3A) (Need to buy WATP) Examination on Stage 3 work Total

9 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: m1m M Fg G, g G r r 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. In much higher orbits they move slower and have a lower acceleration. Gravitational Fields Text Reference pg 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. m1m So Fg r 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. m where F g = force in newtons (N) 1m Fg G r m 1 & m = masses of objects (kg) r = distance apart (m) G = gravitational constant, 6.67 x N m kg 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 10 4 kg. If the centres of the Earth and moon are 3.90 x 10 8 m apart, the gravitational force between them is about 1.90 x 10 0 N. What is the approximate mass of the moon?

10 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 (T v = T sin ) should be the same as the weight (W) and your horizontal component (T h = T cos ) should be the same as the thrust (T) below. Equipment: Set up as shown in diagram: Procedure: 1. Set up the equipment as shown.. 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 40 0 and 65 0 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. Note: Ensure the dowel is level by using a spirit level. 6. Repeat the experiment for two other angles of within 40 0 and 65 0 everything else remains the same. Results: Trial 1 Trial Trial 3 Angle Weight (W) Thrust (P) Tension (T) Trial 1 Trial Trial 3 Vertical component of tension (T v = T sin ) Horizontal component of tension (T h = T cos ) Difference between T v and W Difference between T h 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?. The weight of the beam in this experiment was ignored. Is this reasonable? If so, why? 3. Express the average difference between T v and W as a percentage of W. Do the same for T h 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.

11 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. P lost = I R. Reduce current means reduces power lost as heat. 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 : 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 g ball is attached to a 0.0 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 = 0.0 m F = 30.0 N [1 mark] mv F r 0.1xv x0.0 v [1 mark] v = 7.75 m s 1 [1 mark[

12 Harder 1. A crane lifts 6.00 x 10 kg load of rubble on a building site. The 7.00 m crane arm is uniform and has a mass of.80 x 10 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) x.867) = 1.710T [3 marks] = 1.71T = 1.71 T T = 4318 N T =.43 x 10 4 N [1 mark] r 1 = 3.5 cos 35 =.867 m r = 7 cos 35 = m r 3 = 5 sin 0 = m Drawings and Graphs: Easy recall You are doing a movie stunt. You have to leap from one roof to another.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.) ( marks) One you leave the building, the only force acting on you (assuming no air resistance) is gravity. [1 mark arrow, 1 mark label]

13 Harder (applying physics understanding or interpret a graph) This is from a semester examination. Section Three: Comprehension 0% (36 Marks) This section contains two () questions. You must answer both questions. Write your answers in the space provided. Question : (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 each conductor. The circuit diagram the teacher sets is shown to the right. in up 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 be m and the lengths of wires A and B to be 0.00 m. to The relationship the teacher was investigating can be found from the following formula: F oi1i where: F is the force of wire B on wire A (N) l d lis length of wires (m) o is the permeability of free space I 1 and I 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 marks)

14 The results of the demonstration are shown in the table below: I A I B F (x 10 7 ) I A x I B (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 (I A x I B ). (5 marks) d. State the relationship between the force exerted by wire B on A and the current flowing in the wires. ( marks) It is a linear relationship F being proportional to (I A x I B ) (1 mark) (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 7 80x10 as per graph, gradient = 0 (1 mark) = 4.0 x 10 7 N A NB: should only be 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) F oi1i l d so F I A xi B 0 = l but d F I A xi B = gradient so 4.00 x = l (1 mark) d 4.00 x = 0.01 o = x10 xxx units: Nxm o = 1.3 x 10 7 N A NB: only significant figures, if not, deduct (1 mark) (1 mark) 1 mark A xm

15 1 mark for each of the following: axis correct position axis labelled point plotted correctly line of best fit title