#### Calculating the value of "g" (Gravitational field strength) using a mass on a spring

Calculating the value of "g" (Gravitational field strength) using a mass on a spring Gravity affects all things that have mass and therefore must affect how much a mass placed on a spring will extend. Measuring the time period and extension of a mass on a spring for vibrations should enable us to calculate a value for g. Using the following formula will help us to do this: Formula 1 T=2?Vm/k g (gravitational field strength) affects the spring constant - k in the formula F=ke and because F = weight = mg. Therefore mg = ke and m/k = e/g. We can now change formula 1 to the following: T=2?Ve/g If we rearrange the above formula so that the subject is T2 we should get the formula below: T2 = 4?2 e g Measuring T would allow us to calculate T2 (The time period - to calculate measure the time it takes for a certain number of oscillations and then divide it by the number of oscillations) and e would allow us to plot a graph and, according to the formula if we take the gradient of the line of best fit it will be equal to: 4?2 g We can then work out g, the gravitational field strength. g= 4?2 _ Gradient The graph that will be plotted will be T2 against e (time period2 against extension) and I expect that it will be similar to the following sketch: I predict that the gravitational field strength I calculate will be quite close to the 9.8N/Kg that is taken to be g

#### The aim of this investigation is to ascertain the effect of weight on a child's toy in relation to how high it will bounce.

Physics Sc1: 'Bug-up' Toy Investigation Aim The aim of this investigation is to ascertain the effect of weight on a child's toy in relation to how high it will bounce. Background After playing with the toy, I looked at how it worked. It is a very simple mechanism that is shown above, consisting of a plastic base with a coiled spring wrapped around the centre. On top is a red rubber 'sucker' that grips to the base when you press down. The spring slowly forces the two apart and it then flies up in the air. To find out the energy stored in a spring, you can just apply the equation for work done, replacing distance with compression. This way you get w.d. = Force x Compression. Then, to find out the energy stored in the spring, you need to know the area under the line when it is plotted on the graph, like in the example below: To find out the area, the equation is 1/2 x base x height. This makes the equation for the amount of energy stored in a spring 1/2 x force x compression. The force and the compression on the spring in this toy will always be the same, more or less. This energy stored in the spring will be equal to the toy's gravitational potential energy, as Einstein said that energy cannot be created or destroyed, just changed from one form into another. Providing no energy is lost, the transfer of energy from the spring will be 100% compared to the amount of energy

#### Investigation into factors affecting the time period for oscillations in a mass-spring system.

Investigation into factors affecting the time period for oscillations in a mass-spring system When a mass is attached to the end of a spring the downward force the mass applies on the spring will cause the spring to extend. We know from Hooke's law that the force exerted by the masses attached to the spring will be proportional to the amount the spring extends. F = kx When additional downward force is applied to the spring we can cause additional tension in the spring which, when released, causes the system to oscillate about a fixed equilibrium point. This is related to the law of conservation of energy. The stain energy in the spring is released as kinetic energy causing the mass to accelerate upwards. The acceleration due to gravity acting in the opposite direction is used as a restoring force which displaces the mass as far vertically as the initial amplitude applied to the system and the process continues. A formula that can be used to relate mass applied to a spring system and time period for oscillations of the system is T = 2?VM/k This tells us T2 is proportional to the mass To test this relationship an experiment will have to be performed where the time period for an oscillation of a spring system is related to the mass applied to the end of the spring. Variables that could affect T Mass applied to spring; Preliminary experiments should be performed to

#### To find out if the motion of an elastic band changes the tension, by the rate of its extension

Kirandeep Banga. Year 11 Physics Assessment. Aim The aim of the investigation is to find out if the motion of an elastic band changes the tension, by the rate of its extension. So in other words if an elastic band is extended to 20cm, will it move at a greater distance once its catapulted through the air, then a band which is say extended to 10cm, and if so why? Is the height achieved by the band, related to the amount of tension that exists within the band while its being extended, before it's catapulted? Method To answer the questions asked above, I plan to carry out an investigation, in which I will catapult an elastic band in to the air, which will be extended from various extensions, I will then proceed to measure the distance travelled by each new extension of the elastic band, using a meter rule, and from my result determine certain trends from the graph to answer the questions asked above and to conclude my predictions made for the overall experiment. The length at which the elastic band will be extended to, will start from an extension of 0.02m , and will continue all the way up to 0.08m. Two meter sticks will be cello taped to the wall so that when the elastic band is catapulted, the distance travelled by the band can be measured from the meter stick. The elastic band will be catapulted off the end of another meter stick, in front of

#### An Investigation into the Factors, which affect the Voltage Output of a Solar Cell

An Investigation into the Factors, which affect the Voltage Output of a Solar Cell My aim is to try and find out how much the voltage is affected when exposing different sized areas of a solar cell to a light source. From this I will also establish the energy of each photon and approximately, the number of freed electrons, which can make an electric current flow. I know that light consists of packets or quanta of energy called photons. When electromagnetic radiation such as light shines on materials (usually metals), which emit electrons the light photons containing energy are captured by the electrons. This means that the electron absorbs the energy from a photon thus allowing it to escape from the surface of its material. For each light photon landing on the surface of a material which emits electrons, an electron can be 'free'. I know that solar cells contain thin wafers of silicon protected by glass. When light photons strike the surface of the solar cell, energy from the photon is absorbed by an electron. The electron needs a certain minimum energy to escape the material but excess energy or surplus energy is transferred to the electron as kinetic energy. Thus creating an electric force, this pushes the electrons around a circuit, known as an electric current, when the solar cell is connected up. The size of the voltage depends on the number of flowing or 'freed'

#### Investigate the way in which extension depends on the tension for rubber.

Brendan Lee Tension and Extension Aim: To investigate the way in which extension depends on the tension for rubber. Before I begin to do this experiment I need to know a little more about elastics. I got my self an elastic band and placed it over my forefinger on each hand. I gradually increased the tension of which I was applying. The original length of the elastic band was 3 cm, but when stretched to its furthest length, it had a length of 21 cm. This meant that it had an extension of 18 cm. The band could not stretch any further than this. If I had exerted even more tension the band would have snapped. I also noticed that after being stretched a few times, and then compared to an exact sized band that had not been stretched, that it did not return to its original shape. It had increased in size by a small amount. However if I only stretched the band a little bit each time, it would return to its original size. When tension is applied to the elastic band, the band automatically begins to repel that force that is stretching it, and when released the band moves back to its original position. When the band is stretched something is pulling the band in the opposite direction, a force. Now the band is stretched it has the potential to do work. We know this as if we released the tension on it the elastic band would pull its self back to its original size and shape. The band

#### The aim of this experiment is to investigate whether the colour of light incident on a medium affects its refractive index.

Refractive Index Praveen Ravi G 11 Lab Report Aim - The aim of this experiment is to investigate whether the colour of light incident on a medium affects its refractive index. Background - Refraction is the bending of light when it passes from one medium to another. Refraction occurs because of the change in density in the new medium which changes the amount of obstruction of the light causing the light to deviate from its original path and take a new, shortest one through the new medium. Refractive index is a unique property of transparent and translucent materials. It is governed by Snell's law µ = Sin i / Sin r where i and r are the angles of incidence and refraction respectively and µ is the refractive index and is defined as "A property of a material that determines how fast light travels through it."1 Hypothesis - I believe that the refractive index of a transparent or translucent medium is independent of the colour of light incident on it. Light always travels in a straight line. When a ray of light enters a medium at a certain angle, it is forced to bend because of the change in density in the new medium and thus, a change in obstruction. The ray will have to deviate from its original path and find an alternate, short and straight way through the atoms of the new medium. Any colour of light will have to follow this same path for the shortest and straight way

#### Forces, waves and radiation.

Forces, Waves and Radiation Springs Aim To investigate which factors affect the length to which a coiled spring stretches when a force is placed upon it, and whether the size of the coils makes any difference to the results. Prediction I predict that the heavier the weight placed one spring is, the more it will stretch as the greater the mass, the greater the force of gravity is, pulling the spring. I also think that the bigger the coils are, the less amount of weight the spring needs to stretch to its elastic limit. Apparatus * Wire (plastic coated) * Retort stand * 30cm ruler * Pen (to coil wire) * Slotted mass hanger Method To perform this experiment, I am going to take a length of plastic coated wire and wrap it around a pen, which will make the wire into a circular spring. I shall then be suspending the spring from a clamp and stand. I shall then place my weights on the lower end of the spring. I shall start the experiment by measuring how long the spring is at the starting point which enables me to take the other results accurately. After that task has been completed I shall be suspending a 50g weight from the spring. This will hopefully stretch the spring slightly. I will then measure the length of the spring and take away the starting point measurement, which will then give me an accurate reading of how far the spring has stretched. I shall then perform

#### The experiment involves the determination, of the effective mass of a spring (ms) and the spring constant (k). It is known that the period (T),

Investigation of the Properties of a Spring 14/11/99. Introduction The experiment involves the determination, of the effective mass of a spring (ms) and the spring constant (k). It is known that the period (T), of small oscillations of a mass (m) at the end of a helical spring is given by the formula: T= 2??(m+ms) k In this experiment the same clamp was used for all readings to make sure there were no miss-readings taken due to differences in the way the clamp and stand reacted to the movement of the mass. Also the spring in all readings was the same as, after all the ms and k of two different springs is going to be different and lead to different readings. The things that were varied in the experiment were, the number of slotted masses on the end of the spring and the number of oscillations of the mass to be counted. The number of oscillations (T) will be measured using a stopcock. Which was varied to give a number between 20 and 30. To keep the number of oscillations, for every mass as similar to each other as possible. To help keep the experiment fair. So to find ms and k the following experiment was devised and carried out: A clamp and stand were used to hold a spring in position, onto which varying sizes of mass were placed. These masses were allowed to bob on the bottom of the spring and a specified number of oscillations were timed using a stop

#### Investigation to find a value of g using the oscillations of a spiral spring.

AS / A2 Physics Coursework Name Nicola Morris Teacher Mrs. Farrow Date February 2002 Title / Aim Investigation to find a value of g using the oscillations of a spiral spring. Diagram A2b partial A4c complete + labelled List of apparatus Clamp Stand and G clamp Metre Ruler (0-100 cm) +/- 0.1 cm Slotted mass and mass hanger (0-1kg added in 0.1kg masses) Stopwatch =/- 0.01 seconds Spiral Spring Fiducial Mark Blu-tack Pointer Flag A2d some A4d comprehensive A6d full specification Variables involved (constant and changing) There are two types of variable within my experiment - dependant and independent. In the static experiment, the load is independent, kg, and the extension is dependant, m. In the dynamic experiment, there is the time period, seconds, which is dependant, and the load, kg, which is independent. F=ke, if k is kept constant. If k is kept constant, then my graph will show a straight line through the origin. This shows that F ? extension. In my dynamic experiment, T 2 = 4? 2 m/k . This shows that again, if k is kept constant, my graph will be a straight line, and T 2 ? mass. To ensure that k is kept constant, I always used the same spring and same masses. My range of variables was so that, my mass didn't exceed 0.7kg, as from my preliminary experiments, I knew that this wouldn't exceed the elastic