1. Distinguish between inertial and non-inertial frames of reference.
Frames of reference are coordinate systems or objects with respect to which we take measurements. (1)
A non-inertial frame of reference is one that is accelerating with fictitious or inertial forces. In these frames observers have to predicate the existence of these ‘forces’ to maintain the validity of Newton’s laws.
An inertial frame of reference is one that is moving with constant velocity or is it at rest, holding Newton’s first law of Inertia. No frame is more correct then another, however, some are simpler. An example could be the stars.(2)
2. Analyse the changing acceleration of a rocket during launch in terms of the:
Law of conservation of momentum and
In its simplest form a rocket is a chamber enclosing gas under pressure. A small opening at one end allows this gas to escape, and in doing so provides a thrust that propels in the opposite direction. The engine creates thrust by burning propellants or fuel and expelling the resulting gases. (3)
The Law of Conservation of momentum states that the change in momentum of a rocket and its exhaust gases is zero (as the gases move in one direction, the rocket moves in the other and therefore cancel each other out)*. We can also determine that the momentum of the rocket plus the momentum of the exhaust gases equals zero**, as momentum equals mass times velocity***. The momentum of the exhaust gases remains quite constant and as the fuel is burned and the mass of the rocket decreases, the velocity of the rocket increase to compensate the loss and the rocket accelerates.(4)
The Review on Frames Of Reference In Occupational Therapy
Theoretical AssumptionsHuman development occurs in an orderly fashion throughout the cycleSteps within the developmental process are sequential and none can be skipped. As a person proceeds through the life cycle, he encounters life events and changing internal and external conditions that necessitate reappraisal and change. As in life, during treatment the patient has responsibility for his own ...
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Forces experienced by astronauts
The mass of the system decreases as the fuel is burnt and the exhaust gases expelled. Through Newton’s second law we know that the acceleration is proportional to the thrust and inversely proportional to the mass, therefore as the mass decreases the acceleration increases. Hence the forces on the astronauts increase. The g-forces increase as minimal friction occurs when the density of the atmosphere decreases with the increasing height of the rocket. (5)
3. Discuss the importance of Newtons law of universal gravitation in understanding and calculating the motion of satellites
Simplistically Newton’s Law of Universal Gravitation is that an object attracts every other object in the universe and the two factors that determine the force of the attraction are:
1. The mass of each of the two objects
2. The distances between their centres of mass.
Represented mathematically by:
where, F = force of attraction between objects
G = universal gravitational constant (which is equal to 6.67 x 10-11 N m2 kg-2)
m1 = mass of object 1
m2 = mass of object 2
d = distance between their centres of mass. (6)
Gravitation provides the centripetal force that produces the circular motion that is the satellite’s orbit around a planet. Therefore, it can be said that:
Gravitational force = Centripetal force
A planet revolving around the sun in a circular orbit or radius r, the centripetal force is provided by the gravitational attraction between the planet and the sun. If the mass of the planet is m and the mass of the sun is M, then:
The following expressions can be derived, from the relationships described in the information above:
The Essay on Biomechanics Of Tennis Force Ball Object
Bio-mechanical Principles of the Serve Bio-mechanics is the science that looks at the internal and external factors acting on the human body and the effects produced by these factors. Bio-mechanics studies what makes a body move and the results of that movement. The two main principles of the tennis serve are motion and force. Motion is the "continued change of position of an object in space" ...
The second equation describes the relationship between the radius of an orbit and the period for any (and all) satellites, natural and artificial, orbiting the earth and planets and comets orbiting the sun. It is also Kepler’s third law known as Keplers Law of Periods a necessary consequence of Newton’s Law of Universal Gravitation. (7)
4. Describe how the slingshot effect provides greater speed for space probes
The slingshot effect is also known as a planetary swing by or a gravity-assist manoeuvre. It is performed to achieve an increase in speed and/or a change of direction.
A spacecraft is aimed close to a planet. As it approaches, the spacecraft is caught by the gravitational field of the planet, and swings around it. The speed acquired is then sufficient to throw the spacecraft back out again, away from the planet. By controlling the approach, the outcome of the manoeuvre can be manipulated.
As the probe approaches a planet it is accelerated by the gravitational attraction of the planet, causing it to speed up relative to the planet. As the probe passes the planet, its speed is reduced ,however, relative to the sun, its speed has increased. The probe picks up angular momentum from the planet as it loses an equal amount. (8)
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5. Outline the features of the aether model for the transmission of light
The ancient Greeks spoke of the earth as being surrounded by water, then air and then by the aether. In the mid-seventeenth century it was proposed by a French scientist that motion could only be carried from one piece of matter to another, via contact. So as the planets were in motion, space could not be empty but filled with an invisible substance called the aether, which would allow this motion.
During the nineteenth century, physicists were certain that light was a waveform. They assumed light waves needed a medium through which to travel to us from the Sun and other stars, like all other known waveforms. No medium could be found so one was hypothesized with a set of expected properties. The aether or luminiferous aether was considered as the medium needed to propagate light.
The list of properties proposed for the either included:
1. The ability to fill all of space and be stationary in space
2. It must be perfectly transparent
The Essay on Light Plant Plants Green Red
Let There Be Light Introduction When we look at the sun, what do we see Other than to squint our eyes and put your sunglasses on, you can see that the light is very bright and white-yellow in color. However, looking at light through a prism relates a different story. If Light is put up against a prism it is refracted or bent into a rainbow which contains the primary colors of light in which red ...
3. It should permeate all matter
4. Have a low density
5. and have great elasticity in order to propagate the light waves.(10)
6. Describe and evaluate the Michelson-Morley attempt to measure the relative velocity of the Earth through the aether
The Michelson-Morley experiment attempted to measure the motion of the earth relative to the aether using light and an effect called interference. Interference is the superposition of two or more waves resulting in a new wave pattern.(11)
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If the Earth was to be moving through a stationary aether, there should be an apparent aether wind. The speed of light was supposed to be constant in the aether, so this aether wind should slow down light heading into it, as seen by the observer. The Michelson-Morley experiment compared the speed of such a light ray with another light ray directed across the aether wind. The two rays were compared using an interferometer, a device that displays interference effects. No significant difference was found between the two light rays.(13)
The experiment closely followed the properties of the aether according to the aether model, yet failed to detect any presence of the aether. No matter who did the experiment, where it was done or when it was done, no one was able to physically demonstrate the interference effect that would prove the existence of the aether.
Bibliograpghy
(1) www.dictionary.com
(2) http://cseligman.com/text/physics/inertial.htm
(3) inventors.about.com/library/inventors/blrocketpriciples.htm
(4) www.physicsclassroom.com/class/momentum
(5) Excel HSC Physics – Neville Warren – Published 2008 by Pascal Press
(6) http://www.physicsclassroom.com
(7) http://www.hsc.csu.edu.au/physics/core/space
(8) www.mathaware.org/mam/05/space.exploration.html
(9) www.wikipedia.com
(10) http://www.phys.unsw.edu.au/hsc/hsc/space.html
(11) www.dictionary.com
(12) www.wikipedia.com
(13) http://www.hsc.csu.edu.au/physics
The Term Paper on Light 5
"Visible light" redirects here. For light that cannot be seen with human eye, see Electromagnetic radiation. For other uses, see Light (disambiguation) and Visible light (disambiguation).The Sun is Earth's primary source of light. About 44% of the sun's electromagnetic radiation that reaches the ground is in the visible light range.Visible light (commonly referred to simply as light) is ...
