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If a meter stick moving at 0.90 of the speed of light with respect to the observer would appear to be how long?
Wiki User
∙ 14y ago
--> To get the answer you're interested in, we have to specify that the stick is lined up
with its length of 1 meter pointing in the direction of the motion. It doesn't do any good
to have it standing up straight but moving horizontally. The contraction is only in the
direction of motion.
The contracted length = L sqrt(1 - v2/c2) =
1 sqrt(1 - 0.81c2/c2) = 1 sqrt(0.19) = 0.436 meter
Wiki User
∙ 14y ago
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How would moving at light speed affect a watch?
Just like everything else, that would depend on who is looking at the watch, and how the observer is moving relative to it. To the person wearing the watch, it would appear perfectly normal, as it tick-tocked regularly and the hands moved slowly. But to a stationary observer ... one with respect to whom the watch is moving at light speed ... the watch would appear to have stopped --- just like the heartbeat of the person wearing it!
What is the redshift star?
The redshift is caused by relative motion that increases the distance from the source to the observer. The faster the source of light is moving away to the observer, the greater the redshift
What will be the color reflected by a green surface when yellow light is incident on it?
No light will be reflected, since there is no incident green light to reflect. To a human observer, the surface will appear black.
If two objects moved towards each other with half the speed of light then are they moving at the speed of light relatively?
due to relativistic effects such as time dilation, an observer in either object (an observer in the same inertial frame of reference) will see the other object moving at the speed of lightsee http://math.ucr.edu/home/baez/physics/Relativity/SR/velocity.html for the mathematics behind it
Is it true or false the second postulate of special relativity says that the speed of light in empty space depends on the motion of the source or of the observer?
False. The speed of light in empty space is a constant, independent of the motion of the source/observer. An observer travelling towards or away from a light source at 99% the speed of light would measure light going the same speed as an observer stationary relative to the light source.
How would moving at light speed affect a watch?
Just like everything else, that would depend on who is looking at the watch, and how the observer is moving relative to it. To the person wearing the watch, it would appear perfectly normal, as it tick-tocked regularly and the hands moved slowly. But to a stationary observer ... one with respect to whom the watch is moving at light speed ... the watch would appear to have stopped --- just like the heartbeat of the person wearing it!
how would an observer on train a witch is moving at nearly the speed of light view o'clock on train be which is moving at the same speed and in the same direction?
The clock on train B would appear to be the same width and to run at the same rate
Would a light source moving away from Earth appear blue shifted or red shifted?
A red shift indicates an object that is moving away from the observer, and a blue shift indicates an object that is moving toward the observer. Both of these are called Doppler shifts.
A red shift in the spectrum of the light from an object indicates the object is moving where?
away from the observer.
An apparent shift in the wavelength of light emmited by a light source moving toward or away from an observer is known as?
The Doppler Effect.
What is the redshift star?
The redshift is caused by relative motion that increases the distance from the source to the observer. The faster the source of light is moving away to the observer, the greater the redshift
What is the Doppler effect on sound?
The Doppler effect is a phenomenon observed whenever the source of waves is moving with respect to an observer. The Doppler effect can be described as the effect produced by a moving source of waves in which there is an apparent upward shift in frequency for the observer and the source are approaching and an apparent downward shift in frequency when the observer and the source is receding. The Doppler effect can be observed to occur with all types of waves - most notably water waves, sound waves, and light waves.
What causes light to be shifted?
It is the Doppler effect and is caused by the light source or the observer moving towards or away from each other. In basic terms, if the two are moving toward each other then the light waves arrive at the observer more closely packed than when they left the source. That is, the wavelength is shorter and the light becomes shifted towards the blue end of the spectrum. If the two source and observer are moving apart then you get a red shift.This is analogous to the pitch of a siren which drops as the vehicle passes you and starts receding from you.
When a source of light approaches an observer the light appears to be than it actually is?
Blue shifted and when it is moving away it is under a red shift.
What happens when a star's spectrum is redshifted as a result of the Doppler effect?
With respect to light, the Doppler effect refers to the apparent change in the frequency (and wavelength) of electromagnetic radiation due to the relative motion of the source relative to the observer. When the source (i.e. a star) moves AWAY from the observer, there is an apparent rarefaction (expansion) in the wavelength of emitted light (i.e. frequency decreases), causing a shift in the emission spectrum towards the red side. This is known as redshifting --> the star is moving away from the observer. The opposite happens in blueshift, when the source moves towards the observer.
Does speed depends on time?
When two objects are moving with respect to each other at different speeds, and that difference is a good fraction of the speed of light, then the rate of time passing on one object would seem to an observer on the other object to be different.
What will be the color reflected by a green surface when yellow light is incident on it?
No light will be reflected, since there is no incident green light to reflect. To a human observer, the surface will appear black.
