How is Instantaneous speed measured?
142488
Instantaneous speed, as the name indicates, is measured at a particular instant of time. From a math standpoint, by calculating the first derivative of the displacement function, you can use the result to calculate the speed at any instant of time. In other words, the instantaneous slope of the displacement function is equal to the instantaneous speed.\n\nIf you look at graph of a moving object (displacement vs. time), if you see a steep slope, this means that the object's speed is fast relative to a curve with a moment of shallow slope. How much distance are you moving per unit of time? The more distance you move, the faster your speed. Decrease that unit of time to almost 0, and you'll get instantaneous speed.
229898
it is exactly 299,792,458 meters per second\n\nor 299,792.458 km per second
839651
just go to www.internetfrog.com\n\nclick on test bandspeed\n\nyou will get your current internet speed\n\nother option is just download anything and just watch out the transfer rate per seconds on your screen and you will come to know your exact speed.
1106658
About 18.5 miles per second. 66600 Mph
54242
A change in a objects velocity produces acceleration.\n\nAcceration is a measurement of the rate of change of velocity, and is usually measured in "meters per second squared" or ms^-2.\n\nIf a car is travelling at 5 meters per second, and over a time of 5 seconds, increases its speed to 15 meters per second, it has accelerated at a rate of 10 meters per second over 5 seconds, or 2 ms^-2 (2 meters per second squared)\n\nHope that helps
876839
speed is velocity - both measured as the change of distance divided by the change in time. You may mean the angular velocity, how fast is it spinning; or how fast the air is moving around the center (relative to the air not spinning); or how fast the tornado is moving across the ground.
929319
32 feet per second per second.  The acceleration is constant while the ball is in the air.  It is determined by the force of gravity.  The ball's speed will vary, but acceleration is constant.
874378
If you mean air speed - it is measured in knots.\nIf you mean altitude it is measured in metres.\nIf you mean distance flown - kilometres
1183829
It isn't measured, it is calculated. The speed of light in miles per second is multiplied by the number of seconds in a year to get the length of a light year in miles. \n\nMeasuring the speed of light can be done in many ways, and is not as hard to do as it was before electronics were invented. Early methods relied on flashes of light from rotating mirrors miles apart. Today laser pulses are timed very accurately with electronics over short distances. Also, amazingly, Maxwell's equations calculate the speed of light theoretically from a number of other unrelated electric and magnetic measurements.\n\nMeasuring the distance to remote stars is another topic, but the results are usually expressed in light years because the numbers are just inconveniently large when expressed in miles.
183503
For instance, astronauts have attached a mirror to a rock on the moon; scientists on earth can aim a laser at this mirror and measure the travel time of the laser pulse--about two and a half seconds for the round trip, which gives about 3.00E8 m/s for the speed of light.\n\nIts speed can also be derived from Maxwell's equations for the speed of propagation of electromagnetic fields in vacuum.
918850
If initial speed is V0 and the speed after a time t second is V,\n\nAcceleration is change in speed per unit time.\n\nAcceleration a = (V - VO) / t.\n\nThe average speed during this time t is \n\nV (average) = (V + V0) / 2.\n\nNote; if any quantity is changing uniformly, the average is found by adding the initial and final value and dividing the sum by 2.\n\nThe average speed can also be determined by dividing the total distance by total time of travel.\n \nV (average) = S / t.\n\nTherefore S/t = (V + V0) / 2.\n\nS = (V + V0)* t / 2.\n\nFrom a = (V - V0) / t we have V = V0 +at.\n \nTherefore S = {V0 +at + VO} * t /2 \n--------------- = {2 V0 t + at t } /2\n\n-------------- S = V0t + 0.5 a tt
778567
Constant speed means zero net force.  So what's balancing the air friction?
978564
Velocity is the speed an object is moving at and the direction that it is moving in. For example, if you said that a car was going 60 mph due east you would be talking about velocity; if you merely said that the car was moving 60 mph you would just be talking about its speed. You would measure acceleration by measuring an objects speed at two different times (the closer the more accurate your number estimate), subtract the difference and divide by the time interval. For example, if at time=1, the speed of an object was 5 meters per second, and at time=4 the speed was 14 meters per second you would do the following: (14-5)/(4-1)=9/3=3 meters/sec^2.\nRegarding  your last question, if the skateboard was going 5mph when you started your experiment, then your initial speed would b 5mph.
13383
Tachymeters measure speed. You time how long it took you to run a certain distance or do some given task and that is how fast you did it.
1160553
I am not sure I understand your question in the way it is phrased.\n\nAll measurements need to be taken in a reference frame...it is impossible not to.\nSince there is no absolute coordinate system in the universe, every measurement is relative to the reference frame it is taken in.\n\nFor example,\nlets say that you (meaning in YOUR reference frame) measured a space ship's velocity to be some value, v.\nsomeone on the space ship on the other hand, who is in the Space Ships reference frame, would measure the speed of the ship to be zero and your speed to be v (in the opposite direction).\nIt does not make any sense to say that the space ship is traveling at a speed of v, since that leaves off the reference frame.\n\nOrdinarily (under non relativistic conditions), the reference frame is assumed to be with respect to something at "rest".\nFor example, if you are in a car and look at the speedometer, it might read 55 mph.  This speed obviously does not mean you are traveling at 55 mph with respect to the sun, mars, or alpha centauri, but rather with respect to the surface of the Earth.\n\nIt doesn't just apply for velocities either, it also would apply to distances, times, mass, momentum, energy, .....\nIn different reference frames, measurements can have all sorts of values, each just as "correct" as the next.\n\nSo for all measurements, a reference frame is required to make a measurement.
501038
you just have to divide the speed change of 15km/hr by 5 seconds.\nthat's 3 km/hr/every second
1071909
roughly 11 meters per second, or 24 miles an hour.\n;o)