2006-06-23 23:48:31 · 15 answers · asked by maxamillion 1 in Science & Mathematics ➔ Mathematics
Ok this is a simple problem but in order to solve it we need some other information such as the diameter of revolution. For this explanation I will assume you mean a spinning wheel at 2800 rpm
If the wheel has a diameter x then from the equation 1 below we can calculate the circumference
circumference = pi * diameter (Eq. 1)
For arguments sake we will use inches for the diameter of the wheel it allows for a more straight forward calculation of mph
If we take a point on our wheel and mark it with an imaginary dot for instance for every complete rotation of the wheel our dot has traveld x * pi inches.
Since we know the wheel is revolving at 2800 rpm we can say that in one minute our imaginary mark has revolved 2800 * (x * pi) inches.
since there are 60 minutes in one hour then our mark will travel 60 times this distance thus we can calculate the distance in inches by the following equation.
60 * (2800 * (x * pi)) inches
The brackets are included only for clarity to show the progression of each step.
since there are 12 inches in one foot and 5280 feet in one mile the formula for conversion is as follows
60 * 2800 * x * pi
----------------------- per hour.
5280*12
Thus for a wheel of diameter 10 inches revolving at a speed of 2800 rpm the speed in miles per hour using a value for pi of 3.14159265. The speed in mph is found to be
60 * 2800 * 10 * 3.14159265
------------------------------------- = 8.33 mph
52800 * 12
The general formula for this then becomes
60 * rpm * diameter * 3.14159265
--------------------------------------------- = mph
53800 * 12
Hope this helps
2006-06-24 01:06:39 · answer #1 · answered by Chris 1 · 3⤊ 0⤋
RPM is revolutions per minute. This simplified would mean how many times the wheel turns in one minute.
Now if you measure the outer periphery of the wheel, it woudl measure roughly as much distance if a wheel were to make a full revolution touching the ground (road)
you have to multiply the length of this periphery by 2800 to get value for one minute. this once again multiplied by 60 would give you the distance in one hour.
Also, when we say machine making 2800 rpm, you should also see how many gear up or gear downs are happening between the machine and the wheel. If your wheel is making 2800 rpm then the above holds. Else you have to check the ratio of gears which are transmitting the power.
If the dia of the wheel = r
the periphery woudl be = 2x(22/7)r = (say) P ( 22/7 is known as pie)
per minute distance will be = P x 2800
per hour would be = P x 2800 x 60
2006-06-23 23:57:52 · answer #2 · answered by zain15in 1 · 0⤊ 0⤋
It is not always the spin speed that matters. For example, if you have a machine that spins at 1600rpm, but only does it for 30 seconds, the clothes will be no dyer than a machine that spins at 1200rpm for 3 minutes. Ask in the shop how long the spin lasts. You'll probably get a vacant look in return, but ask anyway. The best washing machines without doubt are Miele. They cost upwards of £700 but are said to last 20 years. For a more modest budget washer with a reasonable spin of 1200rpm, John Lewis is highly rated and comes with a 3 year guarantee. It costs £300. Zanussi actually make the machine and their own name machine is guaranteed only 2 years and is not so highly recommended,in fact....it's crap!. The John Lewis machine has been built using superior components, one of the few washers on sale that has been built to a standard and not a price.
2016-03-27 02:53:15 · answer #3 · answered by Beverly 4 · 0⤊ 0⤋
Too many variables for an accurate answer. If you're talking about a wheel spinning, the outside of the wheel is covering more ground (miles) than the point at the axle. So even though the speed is the same, the distance traveled is different.
2006-06-23 23:52:05 · answer #4 · answered by ghost_of_larry_fine 3 · 0⤊ 0⤋
2800 revolutions - 1 minute
2800*60 revolutions - 1*60 minutes
168000 revolutions - 1 hour
The number of revolutions has to be multiplied by the circumference of the spinning wheel to convert it to distance in miles, and thus the number of miles per hour.
Of course, you have to see if the spinning part of the machine is connected (like grears, but with a conveyor belt) to other wheels and the size of those wheels would matter if they are the ones in contact with for example the floor and they are tyres of a car.
2006-06-24 02:21:08 · answer #5 · answered by Kemmy 6 · 0⤊ 0⤋
I thnk you first have to know the circumfrence of whatever is spinning. In other words you are taking the circle and making it into a straigjt line. Once you have that number you will know how much area is covered in 2800 rpm. You then have to ask how long does it take to go one mile.
2006-06-23 23:57:57 · answer #6 · answered by Ben 4 · 0⤊ 0⤋
Speed at the centre is zero.
Speed at a given radius "r" from the centre is
r (in chosen units of distance) * angular velocity (in radians per unit time)
As there are 2 Pi radians in a revolution the speed is
2Pi *r * (number of rotations per unit time)
Take care not to mix miles with inches/feet etc and minutes/hours/seconds when calculating!
2006-06-24 00:10:54 · answer #7 · answered by x 3 · 0⤊ 0⤋
My maths and such are not the best, but still, I'd say that depends on how far out from the central axis the point you are measuring the speed is at.
2006-06-24 02:07:21 · answer #8 · answered by Kango Man 5 · 0⤊ 0⤋
i dont acctually think u can change rpm to mph because rpm is revelations per minuite and mph is miles per hour.
2006-06-23 23:58:12 · answer #9 · answered by haynes 1 · 0⤊ 0⤋
You need more infomation. How far is the revolution 360 degrees around?
Speed=Length/Time
2006-06-23 23:51:32 · answer #10 · answered by The_Answerer 3 · 0⤊ 0⤋