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.
Hello. I am working on planning to build a small pnumatic tricycle. I got far in my calculations, but not quite finished because I am stuck. If someone could check my math, that'd be great, but my problem starts at the second line.
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1. Let's say...
The speed of light is constant, in what ever direction, that's not disputed. Now in relativity that as I understand light speed constant C is bound up with time, eg faster you go faster time pass for an outside observer but stays the same in your field of reference. Or to put it another way the...
Consider a circle rotating about a point X on its circumference at ##\omega = 2## rad/s. That means all points on and in the circle rotate at the same ##\omega = 2## rad/s.
What are the angular velocities of various different points, say points A, B and C, with respect to the centre O of the...
Hi, I want to measure the motor resistance of a gear DC motor by experimentation and Ohm's Law. Should I measure the current without the gear head, with the gear head, stall current (with gear head) or stall current (without gear head)?
I am trying to obtain values for Equation 4 in...
High school student here. I have just over a month until my AP Calculus exam. I love math and I'm confident that I understand all the concepts necessary to ace the exam.
Here's the catch: Whenever I work with a ticking clock, I either don't finish every question in time or make a bunch of silly...
For example let's a satellite was orbiting the moon which has no atmosphere. If the moon suddenly started spinning twice as fast would it effect the satellite's orbit even though the satellite is separated by the vacuum of space from the moon?
Easier way to put it, if the Earth suddenly spun...
I am currently studying Faraday's law and electromagnets and in class we were told that if you had a coil and say a bar magnet was passed through it the faster the magnetic field was applied to the coil the greater the induced voltage or emf would be. I do not understand why the speed would...
Could einstein's theory be completely wrong if we discovered that the speed of light is different in an another galaxy ( speed light isn't constant) and if we proven that there is particles or objects which moves faster than light by 100 or 1000 times?
Okay this has has been driving me crazy.
I would like to know how a conveyor speed can be calculated on the basis of chain pitch, sprocket PCD & no. of teeth and output RPM of gearmotor.
So here is a practical example I'm having to solve at the moment:
I have to drive a conveyor at a speed of...
Homework Statement
The closest star system is about 4.3 light years away from Earth. A spacetug is able to move a cargo ship at a constant force of g=9.8N/kg times the mass of the cargo ship for many years. Starting from rest, speed up the cargo ship until you're halfway to the nearest stars...
Greetings,
It's been quite a while since I had to do anything with velocity, friction, mass, and practically any physics over simple calculations. My car was hit yesterday while parked. There were no injuries, and it still drives just fine. The collision was hard enough to deploy the other...
Hi - I know that the information that I can provide here is too limited for a totally accurate answer, but is it possible to come up with a reasonable estimate? One vehicle, snow tires, on dry pavement, 6 degrees celsius, is motionless. Second vehicle strikes first in the rear. No evidence of...
Homework Statement
Homework Equations
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The Attempt at a Solution
I've been searching for the relation between the spinning speed and inertia in equation form. I do know that since the skater inertia is smaller the spinning speed is faster but that about it. Any hint would be helpful. One...
Homework Statement
The problem is as follows;
A boy begins to walk eastward along a street infront of his house and the graph of his displacement from the house is shown in the figure. His average speed for the whole time interval is equal to...
Hi!
I am trying to find the time for an electron to accelerate in a uniform electric field from u1 to u2.
In the textbook, I found that time is found by integrating d(u/(1-u^2/c^2)^(1/2))=(qE/m_0)⋅dt
and they get u/(1-u^2/c^2)^(1/2) = qEt/m_0 by integrating from t=0 and u=0 to t=t and u=u
I...
Hi, Simple question. if a ship is getting close to the speed of light its momentum (mass) will continue to increase requiring more energy to propel faster. The fuel in the ship will also gain energy and mass as it accelerates. at C it will require infinite energy because it will have infinite...
A delightful video here
A lecturer derives special relativity in a world of bats and echo location using a bat (sound) clock.
All communication is limited by the speed of sound. (so a parallel of our world and light speed communication)
He ends up observing that in no cases for any observer...
Say a particle cover y=t^2 distance.
at t=1s total distance cover = 1m
at t=2s total distance cover = 4m
at t=3s total distance cover = 9m
at t=4s total distance cover = 16m
So the instantaneous speed at t=2s is 9 - 4 = 5m i.e 5m/s.
To get the instantaneous speed at t=2s and...
here "c" is the speed of light ,
i have a question in my mind and i have no answer for it ,
if two light beams are moving in opposite directions then their relative speed is simply c using the law of velocities addition in case of special relativity
but what if those two light beams are moving...
it is known that einstein's theory has been verified and time slows down for particles that should decay in certain time, takes more time to decay if moving fast.
what makes them behave like that, how moving fast makes time to slow down, is it really time or just maybe this has not been...
Does anyone know or know of the general predictions of the speed at which of coherent system losses coherence to contact with a decoherence system? Is that speed limit faster than the cosmic speed limit?
Hi!
I would like to submit a model glider to a CFD wind tunnel so I can determine what would be its optimum glide ratio and forward speed at this incidence.
I am not supposed to know in advance the range of speed this glider can fly (between stall and structural damage), so the speed I will...
Homework Statement
Hello
I have a video that is 30 fps according to the video information (when i right click on the file). It is stated that the videos were filmed in slow motion at 1/10 of normal speed.
I'm using a standard version of MATLAB to plot points (actual position) on a moving...
Homework Statement
Calculate the diameter of a baby's head if there is a time delay of 96 microseconds between receiving pluses from either side of the skull and the speed of ultrasound can be assumed to be 1250m/s.
Homework EquationsThe Attempt at a Solution
The diameter of the baby’s head...
Homework Statement
During a drop, a bomber decends with velocity v, directed at angle 37 degrees below horizontal. The cargo is released at an altitude of 2450 m and reaches intended dropzone with displacement of 3850 m
What is the speed of bomber when it releases its cargo
Homework Equations...
Could anyone offer me a little help with understanding why the principles demonstrated in Galileo's (probably fictional, I know) experiment involving two spheres of the same mass from a tower don't apply in the following situation please?
As I understand it, the principle is essentially that...
Hi could someone please explain to me what is meant by the term wave speed because I am confused by the definition which states "how fast a point moves on the wave".
I was reading Walter Isaacson's biography of Einstein recently, and I thought of moving walkways in airports.
Let's say we have a pitcher and a catcher on the moving walkway 80 feet apart, and the pitcher throws the ball to the catcher, and the time that it takes to travel from the pitcher to...
Homework Statement
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"An airplane is flying on a bearing of 340 degrees at 400mph. A wind is blowing at a bearing of 320 degrees at 30mph. Find ground speed and direction of the plane."
Homework Equations
vx=vcosϕ
vy=vsinϕ
The Attempt at a Solution
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First, my teacher told us to change...
Hi guys
hoping someone is able to answer this albeit a estimated reply.
I am trying to figure out the speed I was hit at in a recent accident.
I was stationary at a junction (vehicle weight aproz 1470kg) foot on brake
was hit from behind (vehicle weight aprox 2000kg)
was hit full on driver did...
Homework Statement
In the figure, a proton, mass 1.67×10^−27 kg, is projected horizontally midway between two parallel plates that are separated by 0.20cm, with an electrical field with magnitude 7.8×10^5N/C between the plates. If the plates are 5.40cm long, find the minimum speed of the proton...
Hey guys,
Is it possible to travel with high speed beyond a solar system or a galaxy? Or is there something that will prevent something to move at high speed outside a solar system or a galaxy?
Homework Statement
The speed of a particle in Earth's frame is 0.4 c. A second particle goes away from the first one with speed 0.6 c. What is the speed of the second particle in Earth's frame?
Homework Equations
u=(u'+v)/(1+u'v/c^2)
The Attempt at a Solution
I think v=0.4 c and u'=-0.6, but...
Homework Statement
An electron is released from rest in a weak electric field given by -2.8 x 10^-10 N/C [PLAIN]https://www.flipitphysics.com/Content/smartPhysics/Media/Images/Tipler/Symbols/jhatbold.gif. After the electron has traveled a vertical distance of 1.9 µm, what is its speed? (Do not...
It occurred to me that if the speed of gravity is the speed of light, then the universe must be accelerating due to Dark Energy, What my question is do we know the frequency of gravitational radiation, If we do then any compression or expansion of these waves will change the cosmological...
Homework Statement
A uniformly charged thin ring has radius 13.0 cm and total charge 21.5 nC . An electron is placed on the ring's axis a distance 32.5 cm from the center of the ring and is constrained to stay on the axis of the ring. The electron is then released from rest.
Find the speed of...
Homework Statement
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This is a problem from my Differential Geometry course
A velociraptor is spotting you and goes after you. There is a shelter in the direction perpendicular to the line between you and the raptor when he spots you. So you run in the direction of the shelter at a...
The graphs of intensity versus wavelength of blackbody radiation and of number of molecules versus speed in a gas look very similar to me. Is this just a coincidence? They seem like quite different phenomena.
Is it possible to find the speed increase due to gravity pull using the SR velocity addition formula or the calculator here?
http://hyperphysics.phy-astr.gsu.edu/hbase/Relativ/einvel2.html
Can you confirm that it is in accordance with GR formula?
For example, if an asteroid is approaching the...
Hello.
I know that the speed of an object can be calculated the following way:
v = \frac {ds}{dt} = \sqrt{(v_x)^2 + (v_y)^2}
where ##s## is the position and ##v_x = \frac {dx}{dt}## and ditto for ##v_y##
Based on its definition, one should be able to obtain the same result by calculating ##s...
In my textbook.In some question gives me angular speed as ( )rev/s.I know that its the frequency (f).But some questions It says angular velocity and says rad/s.
Interesting thing happens when the textbook says in angular speed and I use f and then using w=2πf and then continue I get wrong...
Someone asked me the other day that
a photon is traveling at c and he is also traveling at c (suppose)
then to him the photon is at rest and so it must have a mass
I could not answer him and so I need some help
I have two codes in C++ that are both working, yet I cannot figure out why one is so much faster than the other. To my knowledge, BLAS with MKL (Intel) should be much faster than GSL (GNU), although my code is showing quite the opposite. Here are the codes themselves where I am simply creating 2...
Suppose there is an enclosed container having air inside at say 4 barA pressure. Now, a hole has been made at one of the walls of the container and by another hole, air is continuously injecting inside so that the pressure wouldn't fall. Now, with what speed the air from the container will come...
Homework Statement
Rock is falling from 10meters 18km/h speed , what is speed of rock just before it touches the ground
Homework EquationsThe Attempt at a Solution
So in meters its like 5m/s and h=10m so t=2s if h=d , v=t*d=2s*10m=20m/s but i think i somehow should include gravity too so I am...