# Questions tagged [braking]

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### Could a mainspring be used to generate train acceleration during starting-up from the kinetic energy stored during its slowing down?

When waiting for the underground, I've always been wondering why we could not absorb the kinetic energy of the train to slow it down at the station and then to release this energy to help it ...
• 183
697 views

### Why can't trains stop in 2x the distance of trucks from the same speed?

It is my understanding that every axle on a modern train has brakes. According to this page https://www.engineeringtoolbox.com/friction-coefficients-d_778.html clean/dry steel on steel has a (static) ...
• 131
62 views

### What will be the force F for the given brake system?

I am getting two ways to find F. One is Fx0.2=30 Nm which gives F=150N Other is Fx0.2-640x0.13=0 which gives F=416N I am confused which one is incorrect. I know problem is too basic but still not ...
5k views

### Why do heavy trucks use air brakes?

I was having a discussion today, which led to the question why do heavy trucks still use air brakes? To my knowledge, it has been used for at least 40 years (I remember that as a kid), and ...
• 22.6k
1k views

### Ways to brake an axle

I am currently studying Mechanical Engineering and am doing an assignment where I have to design a wire rope tensioner where a wire rope is unspooled from a drum, but the wire has to be at a specific ...
• 61
30 views

### Way to keep object on linear rail in the position you leave it in despite smaller external forces?

Problem: I have a rod on a linear rail system. This rod can be pushed forward or backwards. There is air blowing out of the front of the rod (~2 lbf) causing it to move to the back position by default....
1 vote
41 views

### Force necessary to resist motion due to torque on a drum brake

A drum is subjected to a counterclockwise torque of 16 in-lb. What horizontal force is necessary to resist motion? Coefficient of friction = 0.40 Weight is neglected. I'm having a hard time on this ...
• 33
1 vote