paper cones investigation

Investigation Report Aim Theory When an object is dropped in air, it accelerates. If it is allowed to drop far enough then it can reach its terminal velocity. This is the maximum velocity of the object during its fall and occurs when the upward force of air resistance acting on the object equals the weight of the object. So at terminal velocity... (P.31, Complete Physics, 1999, Pople, Oxford University Press, ISBN 0-19-914734-5) (P.33, Physics 1, 2000, Cambridge University Press, ISBN 0-521-78718-1) Looking for a formula for air resistance... F = force of air resistance ? = density of air = 1.2kgm-3 c = coefficient of drag for the object / dimensionless A = cross-sectional area of object hitting the air / m2 v = velocity of the object / ms-1 (http://damonrinard.com/aero/formulas.htm) Looking for a formula for the weight of an object... W = m.g W = weight / N m = mass / kg g = acceleration due to gravity, 9.81Nkg-1 (P.55, Physics, 1991, Robert Hutchings, Nelson, ISBN 0-17-438510-2) So putting these formulae together... From the Physics AS course, v = velocity x = displacement t = time so References to the specification Forces and Motion 2821 Forces, Fields and Energy 2824 Aim of your investigation The aim of this work is to investigate the relationship between the time taken for a paper cone to fall and the mass of the cone. Variables

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Catapult Investigation

Mark Cranshaw 0P/11P Physics coursework Catapult Investigation Planning: * Preliminary work The preliminary part of my catapult investigation was to see how far I could stretch an elastic band without breaking and also to test to see what readings I could use in the final experiment. I am going to plan an experiment where I shall investigate the firing distances of 100g weights fired by two elastic bands wrapped around a stool. First of all we did our preliminary experiment. In this we investigated elastic bands to see which would be most suitable to use in our final experiment. We tested the elastic bands with different forces (1-10 Newton's) and recorded the distances of which they were stretched. I realised that if I stretched the elastic bands with more than a force of 10 Newton's then they would probably break or loose their elastic energy. Here is a diagram showing our trial experiment: The results of this experiment are shown on the graph on the next page and also below: Force (Newton's) Distance stretched (cm) 24 2 29 3 36 4 44 5 54 6 64 7 73 8 80 9 86 0 90 1 05 2 09 3 20 4 23 5 25 From the results it is quite easy to see that the bigger the force on the elastic band the further it will stretch. From this I will make a prediction: "The more force put on the elastic band the further the weight will travel the further the elastic

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The advantages and limitations of electron microscopy.

The advantages and limitations of electron microscopy There are two main branches of microscopy that are pertinent to cell biology. These branches arise from the two types of microscope; the light microscope and the electron microscope. The basic principles of light microscopy have been known since circa 17th century, however improvements in lens manufacture in circa 19th century allowed the use of microscopy to be much more practically available and useful. This is increased ability inspired rapid research into both the design of microscopes and the preparation of specimens. However, the light microscope can only magnify objects bigger than 0.2 micrometres; due to its limited resolving powers. This is because it utilises a beam of light. Relatively, light has a long wavelength, this means that when there are two small points close together there is too much refraction and wave front overlap, the eye then only sees one point. This can also be considered in terms of objects "crossing the path" of the wavelength. The smallest wavelength of visible light is 400nm, the diameter of mitochondria is 1000nm, and therefore mitochondria cross the path of the light wave. However ribosomes have a diameter of 22nm, and do not cross the path of the light wave and are therefore not seen by the light microscope. As biologists came to realise these limitations they understood that the

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investigating the relationship between the diameter and the current in a wire at its melting point

Investigation Report Aim Theory Electrical resistance is a measure of the degree to which an object opposes the passage of an electric current. The SI unit of electrical resistance is the ohm. Its reciprocal quantity is electrical conductance measured in siemens. Resistance is the property of any object or substance of resisting or opposing the flow of an electrical current. The quantity of resistance in an electric circuit determines the amount of current flowing in the circuit for any given voltage applied to the circuit. Some formulae for resistance are where R is the resistance of the object / ? V is the potential difference across the object / V I is the current passing through the object / A (Ref. http://en.wikipedia.org/wiki/Electrical_resistance) where R is the resistance/ ? ? is the resistivity / ?m l is the length of the wire / m A is the cross section area of the wire / m A = ?() = ? where A is area / m d is the diameter / m Putting the formulae together, so (Ref. http://physics.bu.edu/~duffy/PY106/Resistance.html) Aim of investigation The aim of this work is to investigate the relationship between the resistance and the diameter of the wire. Variables Variable Independent / Controlled / Dependent Resistance D Resistivity C Length of wire C Diameter I Prediction Since the theory suggests that So So the resistance should be

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Test of the reed switch capacitors in series and in parallel

School: Class Number: Name: Class: Date: 1th May, 2008 Mark: Title Test of the reed switch - capacitors in series and in parallel Objective - To use a reed switch to measure the capacitance of some real capacitors, including those of series and parallel combinations - To investigate how the reed switch current varies with the frequency Apparatus Reed switch x1 Signal generator x1 Resistance substitution box x1 Battery box with 4 cells x1 Milliammeter x1 Voltmeter x1 Capacitors C1 and C2 Connecting wires Theory Reed switch current In the experiment, the reed switch allows the capacitor to be charged up and discharged rapidly. If a capacitor with capacitance C is charged up at a voltage V, the charge Q stored in it will be equal to CV. If the frequency f is operated by the reed switch, the charging up and discharging process will be repeated f times per second, the charge Q in the capacitor will be delivered to the milliammeter at the same rate. Assuming the capacitor is fully charged and discharged every time, the total charge Q total passing through the milliammeter per second is equal CVf, which is the theoretical current I. And the capacitance of the capacitor can be estimated by the formula C = I/ Vf. Capacitors in parallel If capacitors C1, C2, ..., CN are connected in parallel, the charges stored in each capacitor are shown as

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Are mobile phones a health risk?

Abstract In this report I aim to determine whether or not mobile phones pose a risk to our health. I will explain how mobile phone electromagnetic radiation can be perceived as dangerous, with reference to the EM spectrum. I will cite scientific sources of evidence which support both sides of the dispute, and will come to a reasoned conclusion as to how likely it is that mobile phones are a health risk. I will also evaluate the credibility of the sources used to support my conclusions, and list all the sources used throughout in a detailed bibliography. Introduction Mobile phones are becoming increasingly popular in today's world; with around 80 million handsets in Britain, there are now more mobiles than people [1]. They've become an essential part of our existence, in business, in our daily lives and in keeping in touch with our loved ones - however, there is growing concern that this technology is causing serious health problems throughout the population, such as lasting brain damage and cancer. The Media consistently tends to portray mobile phones negatively, fuelling the public's fears and misgivings: this study aims to determine from the scientific evidence whether or not mobile phones present a risk to our health. Main Points How might Mobile Phones be Hazardous to our Health? After studying numerous publications, I have found that if there are concerns about how

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Energy and its uses

Fundamentals of science. Energy transfer systems UNIT 1 Task 1.3 Types of energy Measurement of energy Examples of energy transfer Dewi Hanks ND Forensic Science Year 1 Table of Contents Contents......................................................................... Page 2 Introduction..................................................................... Page 3 Energy Terminology........................................................... Page 4 - 7 Energy Interconversions....................................................... Page 8 - 15 Risk assessment Burning Peanut............................................. Page 16 Burning Peanut experiment................................................... Page 17 - 19 Risk assessment heating metal block....................................... Page 20 Heating of metal block experiment.......................................... Page 21 - 24 Conclusions..................................................................... Page 25 INTRODUCTION In this report I intend to explain the fundamentals of energy and its Interconversions. In order to do this I will be covering the following topics: Types of energy Measurement of energy Examples of energy transfer I will also include two experiments with their results and in order to show the equations and computations used to show energy transfer amounts and the efficiency of

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Electrical Hazards.

Electrical Hazards, risks of injury or death arising from exposure to electricity. Electricity is essential to daily life, providing heat and light and powering appliances in homes and factories. It must, however, be treated with great care, because the consequences of an electrical fault can be serious and sometimes fatal. Generally voltages greater than 50 volts can present a serious hazard and currents of more than about 50 milliamps flowing through the human body can lead to death by electrocution. A shock occurs when a "live" part of some device is touched, so that current passes through the body. Its severity depends on many factors, including the body's conductivity (the ease with which electricity passes through it). The conductivity is usually small, but can be increased if the body or clothing is wet. The risk of injury also increases according to the size of the voltage or current, or the duration of contact. There is a risk of electrocution (death by electric shock) if current passes across the heart. For example, if one foot is touching wet ground, the risk is greater if the arm on the opposite side touches a high-voltage source than it would be if the arm on the same side did so. Current passing into the body generates heat, which burns the tissue. Electricity can also present less direct risks. Burns are caused when hot surfaces on electrical appliances are

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Internal Resistance of a cell

Topic: Internal Resistance of a cell Aim: To measure the internal resistance and emf (the potential differences across a voltage Source when no current is flowing) and to observe the combination of cells Hypothesis: The emf of the old cell is less than the emf of the new cell but the internal resistance of the old cell is much greater than the new cell. Introduction: Resistance in electricity, property of an electric circuit or part of a circuit that transforms electric energy into heat energy in opposing electric current. Resistance involves collisions of the current-carrying charged particles with fixed particles that make up the structure of the conductors. Resistance is often considered as localized in such devices as lamps, heaters, and resistors, in which it predominates, although it is characteristic of every part of a circuit, including connecting wires and electric transmission lines. (Britannica.2006) The dissipation of electric energy in the form of heat, even though small, affects the amount of electromotive force, or driving voltage, required to produce a given current through the circuit. In fact, the electromotive force V (measured in volts) across a circuit divided by the current I (amperes) through that circuit defines quantitatively the amount of electrical resistance R. Precisely, R = V/I. Thus, if a 12-volt battery steadily drives a 2-ampere

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Solar cells

Solar cells This case study involves researching about solar cells and study the effect internal resistance has on its efficiency. This ties up with our practical investigation where we investigate the internal resistance of a power supply. Sunlight can be converted into electrical energy using photovoltaic cells also known as solar cells. Photovoltaic (PV) cells are made of materials called semiconductors such as silicon. When light strikes the cell, a certain portion of it is absorbed within the semiconductor material1. The energy absorbed by the semiconductor from the light knocks electrons loose, allowing them to flow freely thus making an electric current. Unlike on Earth, there is no atmosphere in space blocking sun light so there is a good supply of sun light energy if positioned correctly, but the disadvantage is that the longer they stay exposed to extreme high temperature the more likely for them to get damaged. Temperature also has a major impact on the internal resistance of the solar cell. This could be detrimental to the space program being undertaken. In this case study, I aim to investigate the internal resistance of a power supply and link the results to a power supply in space i.e. a solar cell. By studying the relationship between external load on current and voltage, the internal resistance of a power supply can be determined. Knowledge gained can be

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