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If the tensions are the same on both sides, the net friction is zero.avast2 said:I have a question about friction between pulley and rope?
Does anyone know how to calculate friction between pulley and rope
I enclosed an example picture
Thank you!
A.T. said:If the tensions are the same on both sides, the net friction is zero.
I was assuming a massless rope.DrStupid said:You may assume zero friction in theory but in reality there is at least static friction. With equal tension all around the pulley I would expect it to be
##F_f \le \frac{\pi }{2} \cdot \mu \cdot F_0##
where ##F_0## is the total force acting on the pulley.
For a practical case, this may help you:avast2 said:I have a question about friction between pulley and rope?
Does anyone know how to calculate friction between pulley and rope
A.T. said:I was assuming a massless rope.
I was referring to the situation as given in the OP's diagram, with equal forces on both rope ends. I agree that this is not realistic, but this assumption implies zero net effect of friction.DrStupid said:I started the derivation for the case that the tension can not assumed to be constant and already realized that the force increases exponentially. Thaks @Lnewqban's link to the Capstan equation I don't need to finish my calculation.
A.T. said:I was referring to the situation as given in the OP's diagram, with equal forces on both rope ends. I agree that this is not realistic, but this assumption implies zero net effect of friction.
Friction between pulley and rope is the force that resists the motion of the rope as it passes over the pulley. It is caused by the roughness of the pulley and the surface of the rope, and it can reduce the efficiency of the pulley system.
Friction between pulley and rope can cause a decrease in the mechanical advantage of the pulley system, as some of the input force is used to overcome the friction. This can result in a decrease in the overall efficiency and effectiveness of the system.
The amount of friction between pulley and rope can be affected by several factors, including the roughness of the pulley and rope surfaces, the weight and tension of the rope, and the speed and direction of the pulley's rotation.
To reduce friction between pulley and rope, you can use lubricants to make the surfaces smoother, use pulleys with ball bearings to decrease contact between the rope and pulley, or use a lighter and less tensioned rope.
Friction between pulley and rope is a common phenomenon in various real-life applications, such as in elevators, cranes, and rock climbing equipment. It is also an important factor to consider in the design and efficiency of pulley systems used in industries like construction and transportation.