A surveyor measures a street to be
$L=100\phantom{\rule{0.2em}{0ex}}\text{m}$ long in Earth frame S. Use the Lorentz transformation to obtain an expression for its length measured from a spaceship
$\text{S}\prime ,$ moving by at speed 0.20
c , assuming the
x coordinates of the two frames coincide at time
$t=0.$
Solution
Identify the known:
$L=100\phantom{\rule{0.2em}{0ex}}\text{m};v=0.20c;\text{\Delta}\tau =0.$
Identify the unknown:
$L\prime \text{.}$
Express the answer as an equation. The surveyor in frame S has measured the two ends of the stick simultaneously, and found them at rest at
${x}_{2}$ and
${x}_{1}$ a distance
$L={x}_{2}-{x}_{1}=100\phantom{\rule{0.2em}{0ex}}\text{m}$ apart. The spaceship crew measures the simultaneous location of the ends of the sticks in their frame. To relate the lengths recorded by observers in
$\text{S}\prime $ and S, respectively, write the second of the four Lorentz transformation equations as:
The observer shown in
[link] standing by the railroad tracks sees the two bulbs flash simultaneously at both ends of the 26 m long passenger car when the middle of the car passes him at a speed of
c /2. Find the separation in time between when the bulbs flashed as seen by the train passenger seated in the middle of the car.
Solution
Identify the known:
$\text{\Delta}t=0.$ Note that the spatial separation of the two events is between the two lamps, not the distance of the lamp to the passenger.
Identify the unknown:
$\text{\Delta}t\prime ={t}_{2}^{\prime}-{t}_{1}^{\prime}.$ Again, note that the time interval is between the flashes of the lamps, not between arrival times for reaching the passenger.
The sign indicates that the event with the larger
${x}_{2}\prime ,$ namely, the flash from the right, is seen to occur first in the
$S\prime $ frame, as found earlier for this example, so that
${t}_{2}<{t}_{1}.$
Relativistic phenomena can be analyzed in terms of events in a four-dimensional
space-time . When phenomena such as the twin paradox, time dilation, length contraction, and the dependence of simultaneity on relative motion are viewed in this way, they are seen to be characteristic of the nature of space and time, rather than specific aspects of electromagnetism.
In three-dimensional space, positions are specified by three coordinates on a set of Cartesian axes, and the displacement of one point from another is given by:
The distance
$\text{\Delta}r$ is invariant under a rotation of axes. If a new set of Cartesian axes rotated around the origin relative to the original axes are used, each point in space will have new coordinates in terms of the new axes, but the distance
$\text{\Delta}r\prime $ given by
Questions & Answers
عند قذف جسم إلى أعلى بسرعة إبتدائية فإنه سيصل إلى ارتفاع معين (أقصى ارتفاع) ثم يعود هابطاً نحو سطح الأرض .
إذا قُذِفَ جسم إلى أعلى ووجد أن سرعته 18 م / ث عندما قطع 1/4 المسافة التي تمثل أقصى ارتفاع سيصله فالمطلوب إيجاد السرعة التي قُذِف بها بالمتر / ث . إن هذه السرعة هي واحدة من الإجابات التالية
light energy (photons) through semiconduction of N-P junction into electrical via excitation of silicon purified and cristalized into wafers with partially contaminated silicon to allow this N-P function to operate.
Michael
i.e. Solar pannel.
Michael
If you lie on a beach looking at the water with your head tipped slightly sideways, your polarized sunglasses do not work very well.Why not?
it has everything to do with the angle the UV sunlight strikes your sunglasses.
Jallal
this is known as optical physics. it describes how visible light, ultraviolet light and infrared light interact when they come into contact with physical matter. usually the photons or light upon interaction result in either reflection refraction diffraction or interference of the light.
Jallal
I hope I'm clear if I'm not please tell me to clarify further or rephrase
every matter made up of particles and particles are also subdivided which are themselves subdivided and so on ,and the basic and smallest smallest smallest division is energy which vibrates to become particles and thats why particles have wave nature
according to de Broglie any matter particles by attaining the higher velocity as compared to light'ill show the wave nature and equation of wave will applicable on it but in practical life people see it is impossible however it is practicaly true and possible while looking at the earth matter at far
Manikant
a centeral part of theory of quantum mechanics example:just like a beam of light or a water wave
Swagatika
Mathematical expression of principle of relativity
given that the velocity v of wave depends on the tension f in the spring, it's length 'I' and it's mass 'm'. derive using dimension the equation of the wave