Physics in Sports. The law of conservation of energy also plays a major role in sports. In football if you kick a ball you are transferring kinetic energy from your foot to the ball.
The importance of physics in Sports Everything from kicking a ball into a goal to running from one side to the other side of the field is based on physics. Physics plays a key role in sports; it can impact on a player either positively or even negatively. Gravity, friction, motion and projectile affects sport in every aspect. How physics affects Sports No matter how hard or high you kick a ball as a result of gravity it will be pulled back down to earth. Although the rate at which it descends may vary on its mass and surface area, it will still have to come down. If thrown at any other angle than 90° it will have a parabolic path (trajectory). Also air resistance and friction will reduce the rate at which the ball moves. The law of conservation of energy also plays a major role in sports. In football if you kick a ball you are transferring kinetic energy from your foot to the ball. From the pendulum balls by the side you can see how energy transfer works. If you lift the ball at left then energy will be passed on to the neighbouring ball and as a result the ball at the end will move the same distance from which it was released on the other side. Similarly in this diagram the character kicks the ball transferring kinetic energy from his foot to the ball. The ball moves and rises and therefore the kinetic energy will be converted into gravitational potential energy.
Explain how excessive exposure to radiation can cause harm.
M4 – Explain how excessive exposure to radiation can cause harm. The amount of radiation given to patients in diagnosis is dependent on how close vital organs and tissues are to the malignant tumour, there are two terms commonly used by scientists when dealing with radiation doses, absorbed dose, the amount of energy received by a mass of tissue, which is measured in kilograms (Kg), It has the unit J/Kg and is called the gray (Gy). Effective dose, if the ionising radiation types are compared using the same amounts of energy, alpha particles cause much biological damage, 20 times more damage than X-rays. In medicine radiation affects different tissues and organs in different ways and so each tissue or organ has a number which is used as a quality factor, the absorbed dose is multiplied by this number to give the figure for effective dose, also measured in J/kg b called Sievert (Sv). Major effects of ionising radiation on the body Injury to living tissue results from the transfer of energy to atoms and molecules in the cellular structure. Ionizing radiation causes atoms and molecules to become ionized or excited. These excitations and ionizations can: . Produce free radicals. 2. Break chemical bonds. 3. Produce new chemical bonds and cross-linkage between macromolecules. 4. Damage molecules that regulate vital cell processes (e.g. DNA, RNA, proteins). The cell can
Gravitation - Kepler and Newton revision notes and calculations.
Gravitation Kepler (1571-1630) has studied for many years the records of observation on planets and summarised three laws. Kepler's Law (1) Each planet moves in an ellipse which has the sun at one focus (2) The line joining the sun and the moving planet sweeps out equal area in equal time (3) the square of the time of revolution of any planet (i.e. T) about the sun is proportional to the cube of the planets' mean distance from the sun I.e. is a constant Interpretation form Kepler's laws (I) Kepler's second law : The area swept out in a very short time interval (?t), neglecting the small triangular region is A The rate of area swept = Hence it is a constant. Compare this equation with the angular momentum = Constant This law is in fact an evidence of conservation of angular momentum. (II) Kepler's third law About 1666, Newton investigated the motion of the moon, and thought that it was the force of gravity to pull the moon and keep it in its orbit NB: Time between full moon is 29.5 days but this due to the earth also moving round the sun, the moon is therefore to travel a bit longer At the earth? surface g=9.81m . This is due to the fact that we are nearer the earth centre than the moon (about 1:60) Newton wanted to find out a relation between the distance and the gravitational force (of acceleration due to gravity g) First trial: Second
Radiocarbon Dating
Radiocarbon Dating ________________ Radiocarbon dating is a chemical analysis used to determine the age of organic materials based on their content of the radioisotope carbon-14, to estimate the age of carbon-bearing materials up to about 58,000 to 62,000 years. Archaeology and other human sciences use radiocarbon dating to prove or disprove theories. Over the years, carbon 14 dating has also found applications in geology, hydrology, geophysics, and atmospheric science. Not all materials can be radiocarbon dated. Most, if not all, organic compounds can be dated. Samples that have been radiocarbon dated since the inception of the method include charcoal, wood, twigs, seeds, bones, shells and water, among others. When plants during photosynthesis they include a certain amount of 14C, the isotope in the atmosphere matches the same level approximately. Through photosynthesis Carbon dioxide is taken in by the plant, which is also ingested by animals, therefore every living organism is continually exchanging carbon-14 with its surrounding area as long as it lives. On the other hand when the organism dies the exchanges stops, so the amount of carbon-14 slowly decreases by radioactive beta decay with a half-life of 5,730+-40 years, half-life is the period of time it takes for the amount of a substance undergoing decay to decrease by half. There are three main types of techniques
The egg drop challenge is not mostly a "shock absorption" exercise; the springiness of the padding around the egg is the determining factor.
Egg Drop Contest Materials List 2 small foam cups 2500 square centimeters of plastic bubble wrap 25 paper tissues 12 cm3 cardboard box Abstract of Physical Principals The egg drop challenge is not mostly a "shock absorption" exercise; the "springiness" of the padding around the egg is the determining factor. A bus without springs is near impossible to drive, while one without shocks feels almost normal until moments when the shocks are needed. What will break the egg is to have a force on the egg greater than the shell can withstand. This can be avoided by distributing the force evenly across the egg's surface. The shell is very strong if the force is well distributed, and very weak if the force is all at one point, or on a small area. You can pierce the egg with a very small force with a needle, yet you can put it between your palms and push with great force without breaking it. If your "padding" is too soft, it will work well until the padding has compressed, and then the egg will experience a large g-force and break. If your padding is too hard, then the egg will break while the padding is being compressed. What is desired is padding that will compress at a rate that gives the egg the longest time to stop. We believe that the best solution is to have increasingly soft padding surrounding the egg in multiple (in our case, 3) layers. Our guess is that firm foam
Force and Newton's three Laws
Force and Newton's three Laws We have all known from a young age that an acceleration is caused by a push or a pull. Today we will express this more qualitatively in 3 laws which are called Newton's Laws. Newton's first Law. Newton's first law really harks back to the early 17th century. It was Galileo who expressed what he called the law of inertia, he stated: "A body at rest remains at rest and a body in motion continues to move at constant velocity along a straight line unless acted upon by an external force." Now you can read Newton's own words from his famous book Principia: "Everybody perseveres in its state of rest or of uniform motion in a right line unless it is compelled to change that state by forces impressed upon it." The problem is that Newton's 1st law goes clearly against our daily experiences; things that move don't move along a straight line, nor do they continue to move for ever. The reason for this is gravity; and there is another reason too, even if you remove gravity there is still friction, and there is air drag. So things will always come to halt. But we believe, though, that in the absence of any forces, that an object, if it had a velocity, would continue along in a straight line forever, and ever, and ever. Warning advanced ideas may be found in the following ... However Newton's first law, this profoundly fundamental law, does not hold in
Galileo's Rolling Ball experiment
Galileo's Rolling Ball experiment Aim: Galileo in his rolling ball experiment investigated the acceleration of a ball rolling down an inclined plane, using a similar setup I will investigate how the time taken to roll down the inclined plane varies with the vertical height change. Theory: When two similar objects are thrown vertically downwards, they are in a state of free-fall. Both objects will hit the ground simultaneously; the force which causes these objects to fall down is the pull of gravity which is also the acceleration of these objects. As the object falls down, its speed increases hence its acceleration increases. Using the equation of motion; S= u t + 1/2 a t2 Since u = o, we can ignore initial velocity so: S = 1/2 a t2 Straight line equation: y = m x + c The variables in this experiment are: S and t2 When compared with the straight line equation: S = 1/2 a t2 y = m x a sin a cos sin = Component of acceleration down slope = g S = 1/2 (a sin) t2 Re-arranging the formula gives: S = 1/2 g t2 = = 1/2 g t2 y-axis gradient x-axis relating this to the equation of a straight line. If t2 is plotted at x-axis and at y-axis the gradient (m) will be equal to 1/2 g therefore, changing the height of the inclined slope and measuring the time period, the value of 'acceleration' can be calculated. =
Motion of a sprinter during a 100m run
Investigation 6.1 Motion of a sprinter during a 100m run Distance moved (m) Time at this point (sec) Time interval for previous 10m (sec) 0 0 0 0 2.50 2.50 20 3.65 .15 30 5.06 .41 40 6.50 .44 50 7.83 .33 60 9.48 .65 70 1.90 2.42 The runner starts off slowly and her speed builds up. This is the curve at the bottom of the graph between 0 and 3 seconds it shows that she is accelerating. Her speed is quite consistent between 3 and 9 seconds. This is the relatively straight part in the middle of the graph. After nine seconds her speed reduces slightly until she reaches the end. This is the curve at the top of the graph and it she that she is decelerating. The gradient at 1.0 seconds is; 51.6 = 3.125 The gradient at 5.0 seconds is; 81.2 = 6.6 These values show that he runner is faster at seconds then at 1 second, as the gradient at 5 seconds is much steeper. Section of race (m) Speed for the section (ms-1) Time at the middle (sec) 0-10 4 .25 0-20 8.7 3.075 20-30 7.09 4.355 30-40 6.94 5.78 40-50 7.52 7.165 50-60 6.06 8.655 60-70 4.13 0.675 In the first two seconds the performer is rapidly gaining speed. She is accelerating from a still position to a speed of 5.2 (ms-1). Her maximum speed is 7.7 (ms-1) she reaches this speed at 6.4 seconds into the race. In the last three-quarters of the run she reaches her maximum speed and it
Torsional Pendulum Preliminary experiment
A2 Physics Coursework Aim: To investigate a Torsional Pendulum. Research and equations: As we are working in circular motion, rather than linear motion, the equations that will help me investigate the Torsional pendulum will have to be derived. Here is how it is derived. Using Force= Mass x Acceleration which is what you use for linear motion, this becomes Torque=Moment of Inertia x Angular acceleration. Using Force= -kx from a simple pendulum, this becomes Force=- Torsional Constant x Angular displacement Therefore This can definitely be compared to a=-?2x and becomes However therefore I then found out the exact expression which allowed me to directly work out I and K. The moment of inertia was simply mL2 However for the Torsional constant I first found the formula for the polar moment of inertia which was Ip=?d4/32 and the angle of twist ?=TL/GIp this was rearranged to T= GIp/L where T is the Torsional constant, then substituting in Ip I got Torsional constant= Using the equation I can now substitute in expressions for I and K to get an overall equation which came out to be: T=2? T=Time Period I=Moment of Inertia of the bar L=Length of wire G= Shear Modulus of material d= diameter of wire The following web pages were used to help me derive these equations: http://www.engin.umich.edu/students/ELRC/me211/me211/flash/tors_derivation15.swf
Task- To make a model sycamore seed that can fly easily and stay in the air so in real life it would have the best chance to be carried away.
Sycamore Seed Experiment Task- To make a model sycamore seed that can fly easily and stay in the air so in real life it would have the best chance to be carried away. Aim In this investigation I have been asked to find out how long it takes for a paper helicopter to fall 2 metres. After doing this I shall investigate other ways of changing the timing of its landing. I shall do this by using a range of variables. These include of: Ÿ Length of wings Ÿ Number of tails *I have chosen to use the variable of the number of paperclips being added to the tail of the paper helicopter that I shall make. The gravitational force, which pulls the object downwards, is called the weight of the object. Isaac Newton stated that there is a gravitational force of attraction between any two objects with mass, which depends on their masses, and the distance between them. I think with this information I can easily say that by adding more and more paperclips on to the tail of the paper helicopter it will gain more weight, which will cause the gravitational force to pull it downwards rather than upwards as there is a bigger mass pulling it downwards. I also chose to use this variable instead of changing the length of the wings because I thought that it would have a much more affective difference in the timing of its landing. *In this investigation in order to get the best results