Questions tagged [friction]
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74
questions
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1answer
40 views
Hydraulic Brakes - Why motorcycle brakes more powerful than bicycle brakes?
I was wondering why motorcycle brakes have so much more stopping power than bicycle hydraulic brakes (Than can be found on mountain bikes for example).
The rotor has a bigger size which gives better ...
2
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1answer
67 views
Calculate max deceleration without front wheel slipping (bicycle)
I am trying to calculate the maximum braking force/deceleration for a bicycle.
Note: the question assumes only the front brake is used
Free body diagram:
For dry tarmac where I know there is enough ...
0
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1answer
19 views
Formula for finding the optimal weight for a given torque and vice versa
Whenever i see videos of two trucks pitting with each other to see who has a stronger, i always see comments that sounds like:
If you load the other truck more it would beat the other one
That truck ...
-1
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1answer
32 views
What is the average energy loss due to rolling friction in contemporary motor vehicles?
Around what percent of energy provided by gasoline is lost as heat due to rolling friction in vehicles? Is this number higher for larger vehicles likes trucks than smaller vehicles like bikes?
...
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1answer
27 views
What is the minimum frictional force required for a vehicle to operate smoothly, retain traction, and prevent any skids?
I am not looking for a specific number of course. I know that it may perhaps vary with different vehicles. However, I'm trying to figure out how to theoretically calculate the minimum necessary ...
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2answers
161 views
What is the exact concept of bearings?
Mechanics books always highlight that the main advantage of bearings is to reduce friction, especially when we talk about them in rotational motion applications. The example of ball bearings is always ...
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1answer
59 views
Calculating optimal angle on a rolling pulley wheel, which holds weight, on a horizontal cable
The 40 kg load on the rope accelerates from 0 to 50km / h in 6 seconds.
The rope is tightened with a force of 500kg while the whole assembly is on it.
The middle pulley is driven by a dc motor.
I ...
2
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0answers
57 views
how to calculate required torque and rpm to through a 160 gram cricket ball horizontally at 160km/h velocity?
I am going to design a bowling machine. In this design, I'm going to use two motors that are being placed vertically and their shaft are attached with two horizontal identical wheels with a space of ...
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2answers
42 views
Faster car drifting (motorsport) when using limited slip vs welded differential
I have been drifting RWD (rear wheel drive) cars for some years now. I tend to think about every engineering solution that other drivers use and how does it work before applying it to my car.
What ...
2
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3answers
73 views
Why is the Bush of a motor not replaced with a ball bearing?
Ball bearing reduces friction to a large extent than sliding friction. Motors use a metal ring called bush which slides against the shaft when the shaft is rotating. If a force is exerted on the shaft ...
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0answers
18 views
How to know which efficiencies to take into account when calculating power of a certain part of a power transmission system?
I have an example which I am not certain about:
So It consists of a friction wheel, whose power $P_{fw}$ we know. The power is used to power the driven machine $Dm$ on a shaft that lies on 2 bearings,...
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0answers
27 views
What type of bearing should I use to allow a ring to rotate around a fixed axle
What type of bearing should I use to allow a ring to rotate around a fixed axle. Axle is horizontal.
The rings inner diameter can be flush with the stationary rod or have a gap as needed. What type ...
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1answer
54 views
Friction factor for wormgear design materials
I'm working on a database which involves geometric design parameters, forces analysis and efficiency and losses for wormgear reduction design systems.
To determine the tangential and axial forces ...
0
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2answers
39 views
How to calculate traction force w.r.t. rotational speed of a shaft mounted at a certain angle on a surface?
I am designing a new mobile robot platform and i need a generic solution for the robot in order to establish a proper mathematical modeling. My question is about calculation of the traction force of ...
0
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0answers
24 views
static and kinetic friction force required to tow a train
Today I saw a youtube video of an All-Electric F-150 prototype towing 1 million+ pounds. It's towing a train on railroad tracks.
How much force does it take to get the train moving?
Once the train ...
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3answers
110 views
Dead mans brake on a hand-pushed wheelchair
Would it be possible to install a dead-mans brake on a wheelchair?
I have been calling around and wheelchairs do not seem to come with a dead-mans brake. With that i mean the brake found on airport ...
1
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1answer
47 views
Pacejka “Magic Formula” tire models origin of the name
It might be a little off topic but I'm trying to find source for why is that model called magic formula? I read that it's a simple function of commonplace functions, a data fitting. Is it simply an ...
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2answers
88 views
Refute my assumption: Bearings Don't Improve Efficiency
If two surfaces rub together with a normal force between them, friction is generated. You could add lubrication between those two surfaces and reduce that friction.
Bearings essentially consist of ...
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2answers
42 views
How to keep lighting “barn doors” open
I have two alum plates (45cm x 20cm x 1mm) that are hinged on the long side with two 30 x 80 hinges (30 x 40 each tang) in the middle, and "L" bracket / 20mm brace at the ends secured with a M4 loc ...
0
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1answer
50 views
What are fluids or “goos” called, that increase friction?
I have a shaft inside a bushing, the shaft has a gear on one end that is supposed to provide resistance to other gears it is driven with.
I'm having a hard time finding the correct term for the sort ...
1
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2answers
65 views
Which design to maximize friction for a device standing on concrete?
I have a device 4cm X 5cm X 15cm that stands on asphalt/concrete/road. So, the device is taller than its base which makes contact with the asphalt.
I want to maximize the friction so that the device ...
1
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1answer
33 views
Effect of friction (or horizontal motion) on vertical surface deformation
I am trying to model the dynamics of some system.
In summary, the system consists of one horizontal linear actuator that drives an object along a planar surface and one vertical actuator that brings ...
1
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1answer
41 views
How do you calculate the chain tension required when compressing bulk material over a conveyor?
Bulk material is conveyed over a slat conveyor, and the material is leveled with overhead rollers while being transported in the conveyor to maintain an even material height. Most of these "levelers" ...
0
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1answer
79 views
Minimum required rolling friction between pulley and the rope
The 40 kg weight accelerates and runs on a rope from 0 to 50 km/h in 10 seconds.
I want to calculate the minimum required rolling friction that I need (acceleration without slipping) to achieve ...
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0answers
29 views
Regarding the ITTC Guidelines for Ship CFD applications
I was reading through the ITTC – Recommended
Procedures and Guidelines - Practical Guidelines for Ship CFD Applications (https://ittc.info/media/4196/75-03-02-03.pdf) document and this little thing ...
2
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1answer
145 views
Material with strongest grip on Aluminium 6061
Attached is an example picture of a clamp that will be attached to a pipe made of Aluminium 6061-T4. The clamp should have very tight grip on the pipe and prevent it from slipping or rotating but the ...
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0answers
118 views
statics exam question about friction
In a statics exam I had the question in the picture attacehd and I had some trouble understanding it. The question is so
Under the effect of torque Mo rotates a wheel (radius r) with constant ...
3
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1answer
96 views
Ideal funnel design for powders
I'm designing a funnel/bottle for a powder. My goal is to have all of the bottle's powder contents come out when inverted. However, the powder has a tendency to stick to itself (like flour or brown ...
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0answers
42 views
Why increasing the coefficient of friction results in evenly distributed load in rolling machines?
I'm designing a rolling machine for reduction of steel ingots of $5 mm$ to $1.96 mm$ thick. I can convince myself using equations why increasing the coefficient of friction (in case of lubrication ...
0
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1answer
806 views
How to find required clamping force of bolts to prevent flange faces from twising due to torque?
I have a gearbox adapter that bolts onto a flange and I need to work out how much clamping force is needed to prevent the faces from slipping and keep the bolts in tension rather than shear when ...
1
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2answers
117 views
Does a washer really increase static friction force?
Suppose I have a bolt that goes through a hole in a plate and is under tension. If I place a washer between the bolt head and the plate, does static frictional force (torque actually) really double? I'...
2
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2answers
249 views
Materials to use for a low friction cable-pull
I'm posting this question on this stack-exchange site, because it appeared to be the one made for this kind of questions. If this happens to not be the case, I'm sorry, I didn't know better. Also ...
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0answers
368 views
How Can You Calculate Force to Overcome Friction From an O-Ring Seal?
I essentially have a piston in a tube that is sealed with an O-Ring and actuated with a solenoid.
The friction of the O-Ring however, is higher than estimated (guessed as far as I can tell) by the ...
0
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1answer
162 views
Pan and tilt mechanism
this is my first project that i am working on. I want to make a IR sensor mount using stepper motors.
I seen this on youtube and would like to make a similar design.
I plan on using aluminium ...
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0answers
40 views
How to make machined plastic part slippery for small dry particles
We have a plastic part that is a receptacle for small ( < 1mm ) particles. It is a disk with a shallow cone shaped indent made using a drill. When a particle is placed in the receptacle it should ...
2
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2answers
189 views
Mechanical device that creates friction when rotating?
I am designing a mock-up aircraft throttle, like one of these:
In an airplane, it it slides forward and backward to control the thrust of the engines. The problem is, I am not sure how to go about ...
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2answers
191 views
Multilayered Bearing Spinner
I have a few questions relating to a multiple layered spinner that uses ball bearings to reduce friction, kind of similar to a fidget spinner. The image below is an example of the multilayered bearing ...
4
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1answer
236 views
Deriving the amplitude of a coulomb (dry friction) damped spring
This is my first time posting anything, but I could not figure out the derivation of the amplitude of the spring for the 4 first oscillations. I am not acquainted with the effect and calculations of ...
2
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3answers
101 views
Building a machine from an ideal physics problem
I have a physics professor for whom I'd like to build a machine. Featured in a problem he is notorious for assigning students, originally from Kleppner and Kolenkow's "Mechanics," the machine causes ...
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0answers
76 views
Torque needed to keep a wheel spinning at high RPM
I have a treaded wheel which is 16'' diameter and 4'' across (trailer wheel).
If I want it to spin constantly at 2750 RPM, what amount of torque do I need to apply to combat friction and air ...
2
votes
1answer
378 views
Does oil actually “attract” dirt?
The conventional wisdom consistently holds that "oil (or grease) attracts dirt", giving rise to the need for seals and dry-lubricants.
But I've always considered that to be loose thinking, the truth ...
0
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4answers
840 views
Brake pad materials for use against an aluminium surface [closed]
For a project that I am a part of, we are in need of a brake pad material for use against an aluminum surface without causing any damage to it. So far through my research, the only safe alternative ...
4
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1answer
66 views
Dimension of the unidirectional mechanical clutch
This is a problem from the book Engineering Mechanics Statics vol-1 by Meriam Kraige.
The elements of a unidirectional mechanical clutch are shown in the figure.A torque $M$ applied to the outer ring ...
3
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1answer
95 views
Normal force between two boards
This is a problem from the book Engineering Mechanics Statics vol-1 by Meriam Kraige
The rectangular steel yoke is used to prevent slippage between the two boards under tensile loads $P$ .If the ...
1
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1answer
44 views
Can the hysteresis phenomenon be considered as a (type of) friction
I was wondering whether the hysteresis (in particular, mechanical motion systems) can be considered under the class of friction.
From theory, I know that the frictional forces are direction, and ...
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0answers
60 views
Spinning a balanced load with DC motor
Enclosed within a consumer electronic, I would like to spin a small balanced load. The device will be rotated relative to gravity, but no other direct forces will be applied to the load. A coreless ...
4
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1answer
650 views
Is a gear usually held on a shaft friction or an adhesive?
So, where I work, we have this arcade game, which is a classic claw machine. IN order to raise the claw up and down the machine makes use of a worm gear, like so:
(although for the meticulously ...
2
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2answers
1k views
Good material for friction disk for a torque hinge?
What kind of material(s) would make a good friction disk, or disks, for a friction hinge, or torque hinge? This will be for the hinge on an arm that needs to be adjustable and also hold it's position ...
3
votes
1answer
106 views
Recreating Focaults Pendulum
I am having issues building a recreation of Focaults Pendulum (basic, inexpensive, undergrad project). At this point, I am going to purchase aircraft cable or suspension cable unless someone can ...
0
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3answers
681 views
Applications with combination of high friction and low wear?
What would be some common applications involving high friction and low wear rates? for example, gear-driven mechanisms which require high friction between the gear teeth but ideally low wear between ...
