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General and Special Relativity
Relativity is the theory stating that all measurements depend on the relative motions of the observer and the observed. The theories of general and specific relativity were both proposed by Albert Einstein.
813 Questions
Why does the level of kerosene in a glass decrease when an ice cube kept in it melts?
Ice expands as it freezes, so it takes up more volume than an equal mass of water. Hence when the ice melts in the kerosene, the liquid water takes up less volume, so the level of the kerosene drops.
The color red is associated with danger and attracts attention because of its long wavelength, making it more visible from a distance. Green and yellow may be more sensitive colors for the eyes, but red is chosen for signaling danger to ensure a quick and immediate response in critical situations.
F=G{[(m1)(m2)]/(r2)}
where
F= Force of gravity between two objects
G= The universal gravitational constant (6.64 * 10-11 N(m/kg2)
m1=The Mass of object 1
m1=The Mass of object 1
In order to achieve a negative gravity or a repulsive force, you would need to have at least one negative mass object, which in general is not seen to be plausible. However, there are other possibilities. See this page for a more detailed answer :
http://en.wikipedia.org/wiki/Anti-gravity
What does Einstein's theory of relativity have to do with the GPS system?
GPS receivers calculate your position using a timing signal which is sent from a number of different satellites. By knowing the time taken by each signal to reach you the receiver can calculate the distance from each satellite and hence your position. Using, distance from satellite = speed of light X time of travel. Inorder to very accurately know the time taken for the signal to reach you it is necessary to correct for the fact that time passes more slowly in a gravitational field. For example, time passes faster for a satellite far away from the earth where gravity is slightly weaker. This is were Einstein's General relativity is used - it can describe how time changes with position in gravtitional field.
If you stand in a lift that is accelerating downwards at a rate of 2 m s-2, you will experience an apparent upthrust that acts against your weight. Your weight (the force that acts in a downward direction due to gravity) is:
W = m g
= mass x gravitational field strength
On Earth, g is about 9.8 N kg-1 or 9.8 m s-2 (both units are equivalent)
W = 50 kg x 9.8 N kg-1
= 490 N (in a downward direction)
The upward force due to your acceleration is given by Newton's second law:
F = m a
= mass x acceleration
= 50 kg x 2 m s-2
= 100 N (in an upward direction)
So the overall weight you feel is the difference between them. So:
W = 490 - 100
= 390 N
Can you travel back in time and kill your own grandpa?
In normal language if some body s grandpa did not exist nor his father nether he would exists . So you cannot kill your grandpa and it is impossible to travel back in time .
the very fact that you are alive means that you did not and will not kill your gradfather. even if you intend to kill him there must be some thing stopping you from doing so as it will mean that you would not be there in the first place. because you exist it means that your grandfather existed and was not killed by you or anyone else. it would be very confusing paradox if you were to kill your grandfather as it would mean that you would not exist. then we must consider that your grandather is still alive as yoou could not havee killed him but then as he is alive you are alive and you would have killed him and so on. but as i have said we will not need to consider this as the fact that you existed means that your grandfather was not killed.
To put it more simply, it is impossible to define a negative interval, so it is impossible to move backward in time, therefore impossible to access the time when your grandfather lived. Time travel is possible only in the restricted sense permitted by relativity. By travelling at relativistic velocities, it is possible to reach a point x years in the future at a cost of less than x years of subjective elapsed time for the traveler. But once there, you can't come back.
TO MAKE THIS EASIER TO UNDERSTAND THE GRANDFATHER PARADOX IS USED IN PHYSICS AS ONE OF THE MANY AXIOMS OF FASTER THAN LIGHTSPEED TRAVEL IF YOU KEPT ACCELERATING PAST LIGHTSPEED TIME WOULD EVENTUALLY STOP AND THEN START MOVING BACKWARDS IN RELATION THE THE TRAVELER AT WHICH POINT IF YOU RETURNED TO EARTH WHEN YOUR GRANDFATHER WAS YOUNG BEFORE HE HAS HIS KIDS AND YOU KILLED HIM YOUR FATHER/MOTHER WOULD NOT HAVE BEEN BORN WHICH MEANS YOU WOULD NOT HAVE BEEN BORN AND IF YOU WERE NOT BORN HOW WERE YOU ABLE TO KILL YOUR GRANDFATHER SEE THE PARADOX NOW.
What is the age limit to join the Indian army?
age limit is 17yrs. and 6 mon. correct not a single day shorter than this date to 21yrs
No. Sound is mechanical energy. Mechanical energy does not have mass. And no form of energy has mass. But energy has a mass equivalent per E=mc2 thanks to Albert Einstein.
What is the minimum speed for relativistic effects?
There is no minimum speed for relativistic effects. Your car is a time machine. Your subjective elapsed time is shorter in a drive across town than it would have been if you had stayed home. The catch is that at driving speed, the effect is very small; your moving clock would read slower by a couple of trillionths of a second, perhaps. In order to get any other answer to your question, you need to specify the degree of relativistic effect you have in mind.
Rather than use a particular fuel, 'warp drive' creates a change in the curvature of space-time continuum. ANSWER: The ship would be able to manipulate gravity and literally be able to pull it's destination towards itself while pushing it's point of origin away from itself this allows travel to any point in space in short periods of time while circumventing the problem of time dilation, however it will require 10x2^27kgs of mass in the form of energy to travel just 10m at faster than the speed of light (c) A warp drive is a hypothetical mode of space transportation. A warp drive bends space as a means of propulsion. The Warp theory is much like surfing. Surfers ride ocean waves with a board. the reason why the surfer and the board move forward is because the wave is moving them. A warp drive will create the same scenario. By distorting space around the center region where the craft is, you could create a "space-time" wave in back of the center region. The wave will distort space in the front of the craft, making space sort of "sink" or become weaker. Much like a tsunami. before the tsunami even hits the shore, the waters recede. The distorted space around the craft is called a Warp Field. You could travel the speed of light, but you still must deal with time dilation. And it would take a lot of energy to create a warp field.
a winner Its not a quote its a riddle. The answer is "e"
Can you explain the theory of relativity in simple terms?
Try reading the book Spacetime Physics, by Taylor & Wheeler, published in 1965 and still in print. I read it when I was in High School and found it very understandable. It uses lots of geometry to explain things and avoids calculus. See if your local library has it or can get it for you from another library that does.
Even a simple explanation of relativity is too long for this site without introducing distortions and misunderstandings that require even more questions and answers to resolve.
