Projectile Motion
.0 Introduction In this project, it was decided to use home-made air launcher propelled by air to observe projectile motion. The air launcher is made from plastic water bottle and the air is released in an instant as soon as the air launcher is blasted off. The air launcher is in a projectile motion as soon as it is blasted off as the only force acting on it is gravity. Data such as flight time, range, highest point and others will be collected to determine the constant of gravity acceleration. Three different materials: rubber, plastic and aluminium, have been used as specified in the requirement of this project. The mass of each material is different but the surface area that is in contact with the air is constant. As the mass of each water bottle is different, the launching pressure for each water bottle is different. Pressure is directly proportional to the launching velocity. To achieve a constant launching velocity, the pressure used has to be varied accordingly. In the experiment, the behaviour of the projectile motion is different from the theoretical prediction. The water bottle will travel less horizontally or vertically. The effect of air resistance will slow down the bottle while it is on its course up. The direction of air resistance is acting in the same direction of the gravity, thus the water bottle is brought slower at a faster rate. On its way
Building the national health information infrastructure for personal health, health care services, public health, and research
Building the national health information infrastructure for personal health, health care services, public health, and research Abstract Background Improving health in our nation requires strengthening four major domains of the health care system: personal health management, health care delivery, public health, and health-related research. Many avoidable shortcomings in the health sector that result in poor quality are due to inaccessible data, information, and knowledge. A national health information infrastructure (NHII) offers the connectivity and knowledge management essential to correct these shortcomings. Better health and a better health system are within our reach. Discussion A national health information infrastructure for the United States should address the needs of personal health management, health care delivery, public health, and research. It should also address relevant global dimensions (e.g., standards for sharing data and knowledge across national boundaries). The public and private sectors will need to collaborate to build a robust national health information infrastructure, essentially a 'paperless' health care system, for the United States. The federal government should assume leadership for assuring a national health information infrastructure as recommended by the National Committee on Vital and Health Statistics and the President's Information
The three different crystallographic planes shown are for a unit cell of a hypothetical metal.
Andy Somody 97300-6222 ENSC 330 Assignment #4 ). a). The three different crystallographic planes shown are for a unit cell of a hypothetical metal. I have completed this question based on the assumption that each of the planes is rectangular. Therefore, the angles between each of edges of the planes must equal 90o. Each of the plane dimensions must completely be enclosed by the boundaries of the unit cell of the metal. Even though there are infinite parallel planes having Miller indices equivalent to those of the given planes, these are not enclosed by the unit cell of our metal. Thus, these equivalent planes do not need to be considered to determine the geometry, crystal system and crystal structure of our unit cell. Although we are given the edge lengths of the three crystallographic planes, this gives no information about the orientation of those edges. Therefore, since each plane is rectangular, there are two possible orientations for each plane. The correct orientation must allow the dimensions of all three planes to be correlated with one another. An initial diagram of the three planes of the unit cell is shown below: We can see from the above figure that one edge of the (001) plane must be equal in length to one edge of the (101) plane. There is only one possible orientation of the two planes that can produce this condition - the alignment of the 0.40 nm edge of
Sedimentation and Fluidisation
Sedimentation and Fluidisation Background: Motion of individual particles in fluids Flow through porous (particulate) media e.g. Galileo numbers, Kozeny's and Ergun's equations. Settling behaviour of concentrated suspensions of fine particles under gravity Observed behaviour in relation to concentration (C) A Clear A Type (a) behaviour Liquid usual if xmax/xmin < 6 c = k c ? k B C C sediment D D (a) (b) 'monodisperse' 'polydisperse' In (a) the boundary between A and B descends down the column until meets C. Modification of settling rates at high C. * Effective density and viscosity increased as large particles settle in a suspension of smaller ones. * Upward velocity of displaced fluid. * Velocity gradients close to particles are increased * Small particles may be drawn in the wake of those larger. * Aggregation rates are promoted at high C. Settling velocities at volume concentrations above infinite dilution Prediction of settling velocities:- ) Use properties of the suspension (?c, ?c) not the (liquid) medium, and use a constant K`` (in place of 1/18) K``x2(?s ? ?c)g uc = ????? [1] µc The effective buoyancy force is readily calculated from suspension voidage (e). ?s ? ?c = ?s ?{?s(1? e) + ?e} = e(?s ? ?) [2] µc is then obtained by experiment or estimated from the Einstein relation using the
Methods Of Particle Size Analysis
2. Methods Of Particle Size Analysis (Some of these are briefly reviewed in Coulson and Richardson 1993) Screening Electronic particle counting (Elzone, Coulter Counter) Sedimentation Optical Methods (i) Microscopy (ii) Laser Diffraction (iii) Dynamic laser light scattering Screening Particles are placed on a screen possessing uniform apertures of given dimensions. Particles capable of passing through the apertures require the opportunity to do so. This is provided by agitation of the load bearing screen for a given period. Particles which pass through this screen can be passed through to a nest of screens of decreasing aperture. The mass retained by each screen is then gravimetrically determined. Screening efficiency is affected by ) Sample load. 2) Particle hardness (in comparison with that of the material of the screen). 3) Duration and intensity of agitation. 4) Presence of large particles which prevent access to screen apertures. Screens are available in a variety of standard sizes and are generally used for material >50?m. Screens of smaller aperture are available but these are often mechanically weak or provide a low proportion of surface as apertures. Such systems are often described as membranes. Classification and separation of many biological particles are performed using membranes. This technology is presented in
How a standard Television works and what understanding of Physics was needed to develop it.
00 years ago it was merely a scientists dream. 70 years ago people such as Zworkyn and John Logie Baird proved the basics possible. 50 years ago owned only by the wealthy, they began to change the world. Today almost every household in Europe has at least one, they are used for entertainment, information and education. This report aims to describe how a standard Television works and what understanding of Physics was needed to develop it. (1) Background Unlike modern Television sets the earliest were almost completely mechanical. The dream that was Television was a machine that could reproduce captured images using light, unlike photographs and film Television would store pictures electronically. The original mechanical Televisions could achieve this but were not alike Televisions based on the Cathode Ray tube (see next page). It is not surprising that the inventor of Television is greatly debated, there are claims of it being a Scotsman, a Russian and the Japanese. It is also a matter of opinion, a Russian called Zworkyn is accredited as inventing the first electrical Television, whilst John Logie Baird is accredited as the inventor of the first commercially possible mechanical Television. It also seems to depend on National opinion. One American Physicist and Historian explained how American companies invented the Television with "People from foreign countries contributed
Investigating factors which affect the period time of a simple pendulum
Investigating factors which affect the period time of a simple pendulum In this investigation, I am going to investigate the factors that affect the period of oscillation of a simple pendulum. A simple pendulum consists of a single oscillating mass with a concentrated mass. The period of oscillation is the amount of time taken for the mass to return to its original position after it is released. A is the original position of the pendulum. As it is released gravitational potential energy is converted to kinetic energy as the mass falls and oscillates from A to -A and back. On earth, some of the energy is lost because of air resistance and friction at the pivot. This loss of energy means that eventually the pendulum will stop oscillating. Factors that affect the period of oscillation: • Length of the pendulum (L) • Angle at which the pendulum is released (Amplitude) • Gravitational Field Strength (g) • Mass (m) The pendulum begins to oscillate when the concentrated mass is displaced from the equilibrium point. When the mass is raised it gains Gravitational Potential Energy (GPE). When it is released gravity acts on it and it moves back toward the equilibrium point. As it loses GPE it gains Kinetic Energy (KE), and when it reaches the point of equilibrium it does not stop but continues past. At this point it has maximum kinetic energy and therefore maximum
The aim of this experiment was to set up, calibrate and use a model focimeter to measure the power of an unknown lens.
The Vertex Focimeter. Aim: The aim of this experiment was to set up, calibrate and use a model focimeter to measure the power of an unknown lens. Introduction: Carl Zeiss developed the focimeter in order to measure the power of an unknown lens, however it was C.J. Troppman who produced the model that we use now. The power of a lens is said to be the ability of the surface to alter the curvature of light, i.e. altering the vergence of the incident light. The need for the focimeter in optical practices is that it enables us to identify the patients prescription from their spectacles, which in turn allows technicians to check whether the final spectacles are of the write prescription. The focimeter can also be modified slightly to measure the vertex power of hard and soft contact lenses. There are several methods of determining the back vertex power of a lens, some of which are more accurate than others. * Neutralisation:- By superimposing trial case lenses of known power on the unknown lens a combination can be found whereby there will be no movement of the image of the target. At this point the unknown lens has been neutralised and its power is equivalent to that of the trial case lenses but with opposite sign. In order to ensure accuracy the neutralising lens must be placed in contact with the back surface of the spectacle lens. This is not always possible with some
Resistance. To solve this question, we need to consider the resistivities, lengths and cross-sectional areas of each of the wires. Resistivity (expressed by the symbol r) is related to resistance by the following equation,
Andy Somody 97300 6222 ENSC 330 Assignment 2 ). Resistance: Resistance is the opposition that a material or body has to the passage of current through it, and this opposition converts electrical energy into heat or another form of energy. Resistance in a circuit is mathematically equivalent to applied electromotive force divided by the resulting current, is typically measured in units of ohms (where 1 ohm = (1 volt) / (1 ampere)), and obeys Ohm's law. Alternatively, resistance represents the real component of impedance in an AC circuit, including any opposition to current flow occurring from capacitive and inductive reactance. Resistivity: Resistivity (represented by the symbol ? and typically expressed in units of ohm*m) is the aspect of the resistance that takes the length and cross-sectional area of a substance into consideration. It is a temperature dependent quantity, but one can use it to determine the resistance of an object if the geometry and temperature of the object are known. Resistivity, the reciprocal of conductivity, can be expressed mathematically by the following formula: where R is the resistance of the material (in ohms), A is the material's cross-sectional area (in m2), and l is the material's length (in m). Conductivity: Conductivity (represented by the symbol ? and typically expressed in units of ohm-1*m-1) is a material's ability to transport
SELECTED PROBLEMS OF MODERN PHYSICS I. THE PHOTOELECTRIC EFFECT
SELECTED PROBLEMS OF MODERN PHYSICS I. THE PHOTOELECTRIC EFFECT . How to demonstrate experimentally that photoelectrons are emitted from an illuminated metallic surface? Ultraviolet light cause emission of free negative charges (photoelectrons) from metal surfaces. We can show this phenomena in a simple experiment. A freshly polished plate of zinc connected with an electroscope is charged negatively. When the plate is illuminated by visible light only, nothing happens (the charge on its surface is constant). But when we illuminate the plate using ultraviolet light, a discharge is observed --> the leafs of the electroscope slowly fall. This is a result of electron emission from the zinc plate. What is important, we see that in case of zinc, the photoelectric effect takes place only when we replace the visible light with ultraviolet, which has a higher light-wave frequency. 2. Explain how the magnitude of photocurrent depends on light intensity. The magnitude of this photocurrent increases in proportion to light intensity.(fig.5.2) But increasing the intensity of light increases the number of photoelectrons, NOT their velocity (so increasing magnitude means growing number of photoelectrons) 3. Explain the dependence between photocurrent and the potential difference existing between a cathode and an anode. When the positive potential difference increases, the