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# Questions tagged [friction]

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1 answer
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### Rover Steering Torque

I would like to calculate the required motor torque to turn a rover wheel whilst the rover is stationary. I have modelled the friction force as a distributed force acting equally along the width of ...
0 votes
1 answer
62 views

### Minimum power required to drive a vehicle with a Swedish type omni wheels

I'm trying to find the minimal power needed to drive an omidirectional 3-wheeled robot. I already asked in Robotics Stack Exchange and they didn't respond yet. From the equation $P=Fv$ I know I need ...
0 votes
2 answers
140 views

### Most efficient electricity generation in a wide flow of water

I'm wondering what the best method is for generating electricity in a wide river. The assumptions here is that it's a strong flowing river. It is very wide and we're allowed to put an electricity ...
2 votes
1 answer
113 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" ...
1 vote
2 answers
208 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 votes
1 answer
25 views

### Friction Clamp/Brake Conundrum

I'm trying to calculate the amount of torque I need to put into my braking mechanism in order to hold up a weight. The weight is 18kg at the end of a 170mm arm. this should result in an approx. 30Nm ...
0 votes
1 answer
37 views

-1 votes
2 answers
200 views

### How to create a friction-based cable exercise machine?

What would be the best mechanism to create a friction based cable machine? The point of this machine to only have resistance to movement not when the cable's stationary and without the momentum of ...
0 votes
2 answers
97 views

### To reduce friction losses, is it better to have one single large ratio stage, or multiple smaller stages for worm gear?

If I wanted to have a 49:1 total reduction, would there be less friction losses with a single stage of a 49:1 or two stages of 7:1 and 7:1? Google has not been much help. My gut says that I should use ...
3 votes
1 answer
87 views

### Why is the open-front bike stem design so widespread despite that it may be inferior to the closed-front design?

Context Even major bicycle corporations have the occasional product recall on handlebars. It's easy to see why. The bike itself is a gentle, light, and nimble ~10 kg (for a road bike) object, whereas ...
0 votes
1 answer
119 views

### Force Required to Keep Ball Rolling

I am attempting to recreate a demonstration that someone told me about. A hollow steel ball rolls around in a non-metalic bowl, electromagnets keep it going. I obtained a steel ball and a glass ...
3 votes
5 answers
4k views

### Is there any material that has a higher kinetic friction than static friction?

Is there a material that has higher kinetic friction than static friction? You can assume it's sliding on any surface you want. Better if you come up with one that has this property on a standard ...
0 votes
2 answers
31 views

### Collecting a released rope with a proper speed

To simplify the problem, I liken the problem to a ship approaching the shore and a device wants to collect the rope in such a way that the rope is neither stretched too much nor released to the extent ...
1 vote
2 answers
99 views

### Passive magnetic bearing coefficient of friction

Imagine two axially-magnetized ring-shaped permanent magnets in a repulsive configuration where one is levitating on top of the other (and somehow radially constrained so the PMs remain ~concentric). ...
0 votes
1 answer
33 views

### Can Friction Pendulum Bearing/System (FPB/FPS) suppresses the effect of an earthquake from every direction or only from one direction?

Can Friction Pendulum Bearing (FPB) AKA. Friction Pendulum System (FPS) suppresses the effect of an earthquake from every direction or only from one direction? Please take a look at the tests which ...
0 votes
0 answers
41 views

### Do asperity junctions break every time a machine starts to rotate?

After reading CONTROL OF MACHINES WITH FRICTION by Brian Armstrong-Helouvry, some questions rised. The main question I ask you is: Suppose two metal surfaces in relative motion first in static ...