In everyday use and in kinematics, the speed (commonly referred to as v) of an object is the magnitude of the rate of change of its position with time or the magnitude of the change of its position per unit of time; it is thus a scalar quantity. The average speed of an object in an interval of time is the distance travelled by the object divided by the duration of the interval; the instantaneous speed is the limit of the average speed as the duration of the time interval approaches zero.
Speed has the dimensions of distance divided by time. The SI unit of speed is the metre per second (m/s), but the most common unit of speed in everyday usage is the kilometre per hour (km/h) or, in the US and the UK, miles per hour (mph). For air and marine travel the knot is commonly used.
The fastest possible speed at which energy or information can travel, according to special relativity, is the speed of light in a vacuum c = 299792458 metres per second (approximately 1079000000 km/h or 671000000 mph). Matter cannot quite reach the speed of light, as this would require an infinite amount of energy. In relativity physics, the concept of rapidity replaces the classical idea of speed.
I understand that if the sun where to 'disappear' then it would take several minutes for the us on the earth to notice as the light takes time to travel. Does this mean that it would also take the same time for us to notice that the gravitational (or electromagnetic) force would disappear too...
This is not homework, it's a problem I came across while trying to model differential braking for my flight simulator. I cannot really see what force pushes the vehicle horizontally and I would really appreciate a detailed explaination.
my question then is that can we ascertain some unknowns about the physical constants of our universe by using video altered speeds , to observe the universe through moving picture frames ? Is there a project benefit in doing more with this ?
I read on the forum that:
"Michelson-Morley results strongly suggested the local speed of light being the same in all reference frames."
I think that's an erroneous understanding. MME only suggested that there is no ether because speed of light is not affected in any direction and remained the...
My query is on highlighted.
This was straightforward. I thought that coefficient of friction ought to lie between ##0## and ##1## maybe i need to check that again anyway;
##F_{lim} = 1.5 ×15000= 22, 500 N##
Using ## v^2 = u^2 +2as## and ##F=ma##
##22,500 = 1500a##...
If I’m not mistaken, the synchronization of 2 clocks to conduct a measurement of the one-way speed of light is not possible since simultaneity is not possible and 2 clocks even if they are synchronized in a midpoint and slowly moved to opposite ends, depends on c being the same in all...
I am interested in making an observation that involves the speed of light. It is widely stated that the speed of light is constant, but without saying what that means. I need to be precise, and would like a reference to an acknowledgement of the problem.
When people talk about the speed of...
As part of an audio-visual I'm producing, I want to video two passing road signs while driving in a car on a country road. The videos have to fit in with commentary and music, so the timing is pretty tight, and I want to get it right the first time I visit the area – 4 hours drive from home...
Hi.
According to Wikipedia: The "one-way" speed of light, from a source to a detector, cannot be measured independently of a convention as to how to synchronize the clocks at the source and the detector.
Mid 20th century, the most precise measurements of the speed of light were done using...
For this problem,
My working,
(a) ##d = a~ly = ac~y##
##v = \frac{d}{\Delta t} = \frac{ac}{b} \frac{m}{s}##
(b) Lorentz factor is ##γ = \frac{1}{1 - \frac{a^2}{b^2}}## Thus time dilation is ##\Delta t = \frac{b}{1 - \frac{a^2}{b^2}} y##, however, I think my arugment is only valid if ##a >> b##...
For this problem,
My working is
(a) ## \Delta t = \frac{a}{\sqrt{1 - b^2}}~ns ##
(b) ## \frac{abc}{(1 \times 10^9)\sqrt{1 - b^2}}~m= d_1 ##
(c) By symmetry, ##d_2 = -d_1##
##-\frac{abc}{(1 \times 10^9) \sqrt{1 - b^2}}~m= d_2##, however, I'm not sure whether my explanation for (c) is enought...
Does the product of Planck's Constant and the speed of light, hc, have any significance in physics other than an arbitrary product of two constants? I noticed that it appears in one formula for the fine structure constant. It also appears in Planck's formula for black body radiation.
Thanks...
Hello,
In this study https://www.ncbi.nlm.nih.gov/pmc/articles/PMC9784821/, the distance the punch travelled from start to impact is 0.49 meters and the time taken from start of punch (that's it, they define the start of punch as the moment the elbow first start to extend) to impact is 0.1...
Is there an explanation for why the speed of light tops out at 186,282 miles per second? Of course that number depends on our definition of miles and seconds. If a mile was 3000 feet then c would be a different number.
But whatever speed it is…. Why that speed? In other words… there is...
TL;DR Summary: This is an astronomy application.
Mentor note: Moved from a technical forum section, so the homework template is missing.
How long does it take a beam of light to reach Earth from the Sun when the Sun is 93,000,000 miles from Earth? Express your answer in seconds, using...
TL;DR Summary: This is an astronomy application.
One light-year is defined by astronomers to be the distance that a beam of light will travel in 1 year (365 days). If the speed of light is 186,000 miles per second, how many miles are in a light-year? Express your answer in scientific notation...
Ok, I took like a class in physics in college. It was a class to learn physics for majors that we really didn't care. I remember him saying, if you remember anything from this class, remember inertia. That's about all I remember from the class... lol.
But, I don't understand why it's...
Hi.
The numerical value of the speed of light ##c## pops out as propagation speed of the wave solutions to Maxwell's equations. It seems like everywhere else we need to plug in ##c## as a parameter. Why is that? Is there a way to "derive" the numerical value of ##c## in other theories, that...
I don't know how to explain it in terms of speed. I know the speed will decrease but if the ray entering the glass at certain angle, let say 10 degrees, the speed will also decrease so what is the relation of speed to the fact that the light will bend or not when entering the glass?
And the...
my answer =
F = 1.6*9.81 - 1.2*9.81 = 3.924 N -> resultant force of the drone moving (weight minus the upward force)
M= 1.2kg , mass of drone
a= 3.31 m/s^2 , acceleration of drone
u=0 m/s , initial speed of drone
t=1s , time
v = 3.27 m/s, final speed of drone
and its not even in the options... 😶
Can someone explain to me what I am doing wrong? Trying to calculate the Temperature T using this formula
I am trying to find T using most probable speed of atoms formula.
T = (V^2) m/( 2k) I am getting riduculous T like 20x10^27. Why?
If number of atoms N= 2x10^24 how do i get mass m? each...
I have been taught that speed of pulse is v = √(T/μ), but here tension varies at each point therefore I cannot just simply apply the formula. I think integration would be needed, I tried but ended up nowhere. Can someone help me find the time?
Sorry, I guess I should have remembered all of this from my school days, but right now I have forgotten so much that I need some help.
I am developing some simple experiments for school children (age ca. 12). This one involving magnets.
I am not asking for detailed calculations, that is way...
Pretty straight forward, ...reason of posting is to check why i am having a negative value for ##a##.
From my study, i know that
##R(||)## to plane
##F - 40 \cos \dfrac{π}{3} = 4a##
##a = -5 m/s^2##
or can i as well have the equation ( friction and tension are at equilibrium) as,
##40...
My answer is R > P > Q = S
Since R is more steeper than P the speed is greater, speed is a non-negative unit so i assume that speed of R will be greater than P
Speed of P has a positive slope, also the magnitude is positive.
Q and S are the same due to the fast that they both horizontal slopes...
We know from double-slit experiments that singular photons behave like waves, so I expect that one photon would undergo refraction when entering, with an angle different than 90 degree, into water, glass or other transparent material. Is that true?
If the refraction occurs, than the speed of...
Started by analyzing the change in energy from the initial position to the final position which gives us mgh=1/2mv^2
Since we are trying to find speed, we rearrange the equation to solve for v, which gives us √2gL.
My question is, do we need to take a component of L for √2gL because it is at...
I tried the square root of ((2)(6.67*10^-11)(3.90E+30))/(5.70E+7)
I got 1.55*10^-5 and that is wrong. Maybe I am using the wrong equation but this is the one of professor gave me and I don't know what I am doing wrong :-(
The question : A car and a truck are both traveling with a constant speed of 20 m/s. The car is 10 m behind the truck. The truck driver suddenly applies his brakes, causing the truck to slow to a stop at the constant rate of 2 m/s2. Two seconds later, the driver of the car applies their brakes...
Hello.
Let's say we have two masses, each moving in 90 percentage of light speed in opposite direction.
Then what will be the speed of the one mass according to an observer in the other mass?
This is what I've done so far:
54 km/h = m/s
72 km/h = m/s
a = 2,0 m/s^2
A = d_1 = v * t = 15 * 10 = 150 m
B = d_2 = v * t = 20 * 10 = 200 m
d_3 = d_1 - d_2 = 200 - 150 = 50 m
Don‘t know how to continue to solve the problem.
To be clear, I'm looking for the speed at which points in space were moving apart from one another in the universe as it existed 370000 years after the big bang, not the Hubble parameter (expansion rate) derived from our current distance within our current time.
Thanks in advance!
I'm trying to wrap my head around the mass vs speed equation of mechanical power.
If you double mass, you double power. If you double speed, you quadruple power...
Fine, but what does that tell us about the relative importance when things aren't doubled?
Let's say boxing Agent 1: has 3%...
The title is from a great book by Eric Kraft, who plays around with one's physical-being in elemental terms in an excellent novel. He is very funny.
To get down to my question: Do electrons or photons on anything move faster than the speed of light?
For example, does even a tiny boost to an orbiting object widen its orbit a tiny amount?
Let's use a hypothetical teleporting asteroid in orbit around the sun. If we teleport the asteroid a millimeter outward, then a kilometer inward, then an AU outward, does its orbit slow a tiny amount, then...
I passed a motorcycle on the highway going the opposite direction. I know I was doing 125/km/h. I estimated that the frequency of his motor dropped by an entire octave, so that's a doubling of the wavelength.
My intuition is telling me that's extremely unlikely. I can't actually calculate how...
A spaceship moves at half the speed of light, what will be the results of measuring the speed of light for it: in relation to the light source it is approaching and in relation to the light source from which it is moving away?
Why is Desmos (graphing calculator app for Android, ios, windows, etc) far faster than everything else in calculating?
I've done the same calculations in Mathematica, Maple, hp prime pro app on windows (ios and Android), various calculator apps on ios and Android, etc
This is one of the things...
This is a famous book in India. I was wondering if one could say if the answer should include velocity or speed. I mean, I don't think there are any details which hint at velocity. We are gives speed in the question and we are asked to find out the distance traveled, this hints we are asked to...
Hello everyone,
I hope you are all great. I am writing down to all of you concerning a problem of mine. I am struggling to generate a trackmap based on Speed (m/s) and G-Forces on excel.
I followed a topic created 12 years ago but unfortunately it is closed ...
The theory of relativity is based on two key principles: the principle of relativity and the constancy of the speed of light.
The constancy of the speed of light is one of the fundamental postulates of the theory of relativity.
Which statement is wrong?