Trying to figure out the forces needed to push a heavy sliding door.

In summary, the problem at hand is designing a sliding door with 4 wheels and a rolling coefficient of 0.03. The initial approach was to calculate the force needed to push the door using the force applied by the door on all 4 wheels multiplied by friction. However, the question arose of whether other factors, such as inertia, needed to be considered. It was determined that in order to overcome inertia, a force would need to be applied to accelerate the door from a stationary position to a desired speed. Additionally, there will be energy loss due to rolling friction and the need for guides on the ceiling to prevent the door from moving to the side. The initial force required to move the door may also be affected by the wheels sinking
  • #1
CuriousNotion
5
0
I have been working with Physics for a while. I have recently come across a problem I could not solve efficiently. I have been designing a sliding door with 4 wheels with a rolling co efficient of 0.03. I thought that if I simply be using Force applied by door on all 4 wheels multiplied by friction I could find the force needed to push the door. However I just want to know if there are any other important factors I need to take into account (Im not sure how to incorporate Inertia)
 
Physics news on Phys.org
  • #2
Well, if the door is initially still...you need to break this tendency of it to stay still...you need to apply a force to accelerate the door (F=ma) from v=0 to some reasonable speed v=v1 at which point (if you need to continue to open the door more) you can maintain such speed for a few more inches (at F=0.03*...) and THEN let go...

So, it all depends how quickly you want to open the door..you can accelerate at various rates...
 
  • #3
Yes, there will be some energy required for inertia. But this is pretty small. Only 1/2mv^2, and v is going to be pretty small, so the energy required to overcome inertia is very small.

While the door is moving, the biggest energy loss is probably rolling friction. But the door will probably also require guides on the ceiling, so that the door doesn't move to the side. The friction between the door and these guides will also cause energy loss. By guides, I mean like grooves attached to the ceiling.

When you start to move the door from rest, you will notice it seems to take more force than when the door is already moving. This will be due to the wheels having sunk very slightly more into the floor, making it hard to move the door at first.
 
  • #4
You can also approximate such a force via FT = mv assuming the force is a fixed value.
For more, see IMPULSE in wikipedia for example...

http://en.wikipedia.org/wiki/Impulse_(physics [Broken])
 
Last edited by a moderator:
  • #5


First of all, it's great that you are using physics principles to design your sliding door. In order to accurately determine the force needed to push the door, there are a few other factors you should consider.

One important factor is the weight of the door itself. The heavier the door, the more force will be needed to overcome its inertia and get it moving. Additionally, the angle at which the door is being pushed can also affect the force needed. If the door is being pushed at an angle, you will need to take into account the component of the force that is acting perpendicular to the door.

Incorporating inertia into your calculations can also be done by considering the mass of the door and its acceleration. The equation F=ma (force equals mass times acceleration) can be used to determine the force needed to accelerate the door to a certain velocity.

Another important factor to consider is air resistance. As the door is being pushed, it will experience air resistance which will require additional force to overcome. This can be calculated using the equation F=0.5ρAv^2 (force equals half the density of air times the area of the door times its velocity squared).

Lastly, it's important to keep in mind that the coefficient of friction you are using may not be accurate for all surfaces and conditions. Factors such as surface roughness and lubrication can affect the coefficient of friction and therefore the force needed to push the door.

In conclusion, in addition to the force applied by the door and the coefficient of friction, you should also consider the weight of the door, the angle of push, air resistance, and the accuracy of your friction coefficient in order to accurately determine the force needed to push the sliding door.
 

1. How do I determine the required force to move a heavy sliding door?

The force needed to push a heavy sliding door is dependent on several factors, including the weight of the door, the type of sliding mechanism, and the friction between the door and the track. To determine the required force, you can use the formula F = m x a, where F is the force, m is the mass of the door, and a is the acceleration needed to move the door. You may also need to consider the coefficient of friction between the door and the track to calculate the exact force needed.

2. What is the best way to reduce the force needed to move a heavy sliding door?

The easiest way to reduce the force needed to move a heavy sliding door is to reduce the friction between the door and the track. You can achieve this by lubricating the track or using a low-friction material for the door or the track. Additionally, you can use a counterweight system or a motorized mechanism to assist with the door's movement.

3. How does the weight of the door affect the force needed to move it?

The weight of the door directly affects the force needed to move it. The heavier the door, the more force will be required to push it. This is because the formula F = m x a shows that an increase in mass will result in an increase in force needed. Therefore, it is essential to consider the weight of a sliding door when determining the required force to move it.

4. What role does the type of sliding mechanism play in determining the force needed to move a heavy sliding door?

The type of sliding mechanism used for a heavy sliding door can significantly impact the force needed to move it. For instance, a roller mechanism with bearings can reduce the friction and make it easier to push the door compared to a trackless sliding mechanism. It is crucial to consider the type of mechanism and its efficiency when calculating the force needed to move a heavy sliding door.

5. How can I make sure that the door slides smoothly without requiring excessive force?

To ensure a smooth and effortless sliding motion, it is essential to maintain the door and the sliding mechanism regularly. Keep the track clean and lubricated to reduce friction, and check for any damaged or worn-out parts that may impede the door's movement. Additionally, using a counterweight system or a motorized mechanism can help distribute the force needed to move the door and make it slide smoothly.

Similar threads

Replies
52
Views
3K
  • Other Physics Topics
Replies
29
Views
5K
Replies
11
Views
5K
  • General Engineering
Replies
5
Views
4K
  • Other Physics Topics
Replies
1
Views
1K
  • Introductory Physics Homework Help
Replies
19
Views
3K
Replies
13
Views
3K
  • Introductory Physics Homework Help
Replies
7
Views
2K
  • Introductory Physics Homework Help
Replies
1
Views
2K
  • Other Physics Topics
Replies
4
Views
4K
Back
Top