Minimum kgf/N for a 4m x 2.5m Door - Outdoor Wind Resistance

  • Context: High School 
  • Thread starter Thread starter josh.k.abbott
  • Start date Start date
  • Tags Tags
    Minimum Resistance Wind
Click For Summary

Discussion Overview

The discussion revolves around determining the minimum force (in kgf or N) required for a magnet to hold a 4m x 2.5m outdoor door open against wind resistance. The focus includes practical considerations for magnet strength and the conditions under which the door may be subjected to wind forces.

Discussion Character

  • Exploratory
  • Technical explanation
  • Debate/contested

Main Points Raised

  • One participant, josh, inquires about the minimum force needed from a magnet to hold the door open outdoors.
  • Another participant suggests that the required magnet strength depends on whether the magnet is self-supporting or tied to something, and mentions the importance of the door's material conductivity.
  • A participant provides a specific product link and states that the magnet has a holding power of 490 N, which could be sufficient if the door's weight is significantly less than this value.
  • Another participant notes that while the specified holding power is adequate for a lighter door, high winds can exert much greater forces, potentially complicating the situation.
  • One participant raises a practical consideration about the wind speed at which the magnet should be able to overcome, suggesting that lower wind speeds may be less problematic than higher gusts.

Areas of Agreement / Disagreement

Participants express varying views on the necessary strength of the magnet and the factors influencing its effectiveness, indicating that multiple competing perspectives remain without a clear consensus.

Contextual Notes

Participants mention the influence of wind speed and the weight of the door, but do not resolve the specific calculations needed to determine the exact holding power required.

josh.k.abbott
Messages
2
Reaction score
0
Hi

What is the minimum kgf (or N) of a magnet to hold a 4m x 2.5m door?

The door will be outdoor and wind can hit it. The function of the magnet is to keep it open.

Best regards
josh
 
Physics news on Phys.org
depends on the strength of the magnet and how you plan to keep the magnet in place. if you want the magnet to keep itself in place, then it needs to weigh just as much as the door. if you tie it to something then it may be able to hold.
it also depends on the conductivity of the door's materials. a 2 tesla magnet, is pretty expensive, but can create forces of roughly the same magnitude as one can pull or push with a hand.
 
fortunately for you that website is telling you what the holding power is. It says that given that you use a VDS coil on the door, so that the magnet is in touch with the coil, the holding power is 490N, which translates to an object as heavy as roughly 49kg. So if the door is only say 20kg, then there's some degree of strength even with the winds. Although high winds can achieve much higher forces, on occasion.
 
On a practical note, maybe you want the magnet overcome at a lower wind speed than a higher one. A 10 km/hr breeze slamming a door shut won't be quite as annoying as a 90 km/hr wind gust doing it.

KABOOM!
 

Similar threads

  • · Replies 42 ·
2
Replies
42
Views
4K
  • · Replies 13 ·
Replies
13
Views
3K
  • · Replies 8 ·
Replies
8
Views
5K
  • · Replies 24 ·
Replies
24
Views
7K
  • · Replies 4 ·
Replies
4
Views
2K
  • · Replies 46 ·
2
Replies
46
Views
9K
  • · Replies 10 ·
Replies
10
Views
5K
  • · Replies 6 ·
Replies
6
Views
3K
  • · Replies 27 ·
Replies
27
Views
11K
  • · Replies 2 ·
Replies
2
Views
3K