1

General Science / How to calculate fan power - formula?

« on: 05/05/2018 08:30:56 »

How can I calculate fan power in these two cases?

The first case is direct wind speed of 10 m/sec.
The fan diameter is 40 cm. The fan housing is shown in the figure.
How to calculate a number 'rpm per second'.

The other case is when the housing is a cone and the fan is 20 cm in diameter.

How to calculate the rotational strength?
In which case is the power of rotate higher?
Is there any formula in the calculation?

I found some formula P=1/2*p*a*V3
 [ Invalid Attachment ]

2

Physics, Astronomy & Cosmology / Which magnet has the strongest magnetic field at its North pole?

« on: 27/10/2017 10:27:21 »

Which of the magnets in the image below has the strongest magnetic attraction on the North pole (in order).
I think the order follows (B, C, D, A)
With magnet 'A' the thickness exceeds the diameter dimension (thickness may weaken its magnetic force on the poles)?

Am I right?


magnets-power.png (18.23 kB . 1092x733 - viewed 2291 times)

3

Physics, Astronomy & Cosmology / Is it possible to make a shield to block a magnetic field?

« on: 23/09/2017 13:40:43 »

Can anybody tell me, is there a chance to make a shield from a magnetic field?
If there is a possibility, what materials should I use?


sh.png (81.75 kB . 472x539 - viewed 13401 times)

4

Physics, Astronomy & Cosmology / How is magnet size and shape calculated to provide a given magnetic field?

« on: 20/09/2017 20:55:04 »

Please experts on the science of magnetism if they can help me.

I need to calculate the dimensions of the magnets in relation to its weight and the magnitude of the magnetic field.

In the image below you note that I want to raise a magnet 'C' for 45 degrees up.

I'm interested in how to find the optimal characteristics of magnets (dimensions, volume, weight, size). The thickness of the magnet must be 30mm.
Topic related to this topic https://www.thenakedscientists.com/forum/index.php?topic=71383.0

The process flow in the picture below would be the following:
By bringing the magnets 'A' to the magnet B, the magnetic field the magnet must be rejected 'B' in a circular arc so that the magnet is lifted 'C' for 45 degrees.

All magnets must be of the same dimensions, weight and volume.
How to calculate the strength (grade), the volume and dimensions of the magnet, so that the power of rejection of 'A' and 'B' magnets, he could lift up the 'C' magnet by lever.

My apologies to the bad English. I hope that you will understand my problem.
Thanks in advance for possible help


magnetup.png (13.95 kB . 739x707 - viewed 5775 times)

5

Physics, Astronomy & Cosmology / How does making holes in a magnet affect the magnetic field?

« on: 17/09/2017 20:12:31 »

This thread is related to this one https://www.thenakedscientists.com/forum/index.php?topic=71383.0
If there are holes in the magnet, do they reduce its magnetic field (ie. the power of the magnetic poles)?

withholes.png (2.28 kB . 412x241 - viewed 2701 times)
My regards to all members

6

Physics, Astronomy & Cosmology / What arrangement of magnets produces the greatest magnetic field strength?

« on: 14/09/2017 11:08:08 »

My apology if I made a mistake to the forum group. Please moderator to move the thread to the appropriate group.

Since I do not have an instrument for measuring the strength of the magnetic field, I thought to ask the here.
I seek the help of experienced experts who understand in magnets, magnetic field lines and the power of the magnetic field.
Which of these three variants in the picture has the strongest magnetic field in the ellipse zone in the north pole of magnets (whether it is a single magnet or multiple connected to one and which zone).
Zone 1a, 2a and 3a are located opposite the magnets,
Zone 1b, 2b and 3b are under 45° degrees.
Does anyone have any experience or perhaps an gaussmeter that can measure the strength of a magnetic field on their own?
I'm interested in the greatest distance at which will begin to attract other magnet (or a piece of metal)
Where is the power of attraction of the magnet stronger. Opposite or under 45° degrees? and which variant?

aaasss.png (15.1 kB . 874x661 - viewed 7293 times)