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Physics, Astronomy & Cosmology / Re: What is a tensor?
« on: 27/04/2016 11:30:56 »Quote from: Arthur Geddes
if i'm accelerating at 9.8 m/s2, why am i not going the speed of light? I'm old enough, to be sure.If we apply some physics from early high school, you would expect your velocity to be:
v = at where:
v: velocity at time t
a: acceleration (9.8m/s2 in this example)
t: elapsed time
According to this formula, to reach the speed of light v=c=3x108 m/s would take t=3x108/9.8 = 3x107 seconds = 347 days, or just under a year.
However (and it's big however!), Einstein showed that you can never accelerate a massive object to reach the speed of light - no matter how hard you accelerate, or for how long.
These concepts normally come up at the end of high school or early university physics.
We don't notice it with our daily lives here on Earth, but when you accelerate objects close to the speed of light, strange things occur: time slows down, and mass increases, so it gets harder and harder to get closer to the speed of light. Oddly, this is not visible to the person being accelerated.
Such peculiarities are very familiar to physicists at the LHC, who try to get particles traveling as close as possible to the speed of light so they can do experiments at very high energies.
See: https://en.wikipedia.org/wiki/Speed_of_light#Upper_limit_on_speeds
So you may feel old, but you are not nearly old enough to reach the speed of light, when accelerating at 9.8m/s2!