What would friction be in this pulley system

In summary, the conversation discusses a system with a mass hanging from a frictionless pulley and another mass on a table. The weight of the hanging mass causes the block on the table to slide with an acceleration, and there is friction between the block and the table. The coefficient of kinetic friction for the setup is calculated using the formula T(rope) - fk = ma and setting it up for both masses. The final result is uk = 0.438.
  • #1
spectravoid
11
0
1. You have a mass hanging off of a frictionless pulley (massless string). The other mass is on a table. The weight of the mass causes the block on the table to slide at an acceleration. There is friction between the block and the table. What would the coefficient of kinetic friction be for this set up?



2. F = ma
w = mg




3. Well Since the system is accelerating, I thought it was

T(rope) - fk = ma
Acceleration and the masses are known. T isn't.

But you can set this up for both masses

T(rope) - ukm1g = m1a
T(rope) - m2g = m2a
T(rope) = m2g + m2a
m2g + m2a - ukm1g = m1a
-ukm1g = m1a -m2a - m2g
-uk(0.483)(10) = 0.483(1.66) - 0.25(1.66) - 0.25(10)
uk = 0.438

Does this make sense?
 
Physics news on Phys.org
  • #2
In the second equation g and a are in the same direction. Hence they must have the same sign.
 
  • #3


I would respond by saying that the coefficient of kinetic friction for this setup would be 0.438. This value was calculated using the equations for Newton's second law (F=ma) and the forces acting on the system (tension in the rope and friction between the block and table). The negative sign in the equation indicates that the direction of friction is opposite to the direction of motion. This value is reasonable and makes sense in this scenario. However, it is important to note that the coefficient of friction can vary depending on the surface materials and conditions, so this value may not be the same for all pulley systems. Further experimentation and analysis would be needed to determine the exact coefficient of friction for this specific system.
 

1. What is friction in a pulley system?

Friction in a pulley system is the resistance force that occurs when two surfaces rub against each other. In this case, it refers to the force that opposes the motion of the pulley as it rotates.

2. How does friction affect the efficiency of a pulley system?

Friction can decrease the efficiency of a pulley system by converting some of the input energy into heat. This results in a loss of energy and reduces the output force of the system.

3. Can friction be reduced in a pulley system?

Yes, friction can be reduced in a pulley system by using lubricants, such as oil or grease, between the moving parts. Additionally, using smooth and polished surfaces can also help reduce friction.

4. What factors affect the amount of friction in a pulley system?

The amount of friction in a pulley system depends on factors such as the weight and material of the objects being pulled, the type of surface in contact with the pulley, and the amount of force applied to the system.

5. How can friction be calculated in a pulley system?

The friction in a pulley system can be calculated by multiplying the coefficient of friction between the surfaces in contact with the pulley by the normal force acting on the pulley. The normal force is the weight of the object being pulled or supported by the pulley.

Similar threads

  • Introductory Physics Homework Help
Replies
5
Views
1K
  • Introductory Physics Homework Help
Replies
3
Views
788
  • Introductory Physics Homework Help
Replies
5
Views
4K
  • Introductory Physics Homework Help
Replies
4
Views
992
  • Introductory Physics Homework Help
Replies
7
Views
7K
  • Introductory Physics Homework Help
Replies
10
Views
2K
  • Introductory Physics Homework Help
Replies
11
Views
2K
  • Introductory Physics Homework Help
Replies
3
Views
1K
  • Introductory Physics Homework Help
Replies
4
Views
2K
  • Introductory Physics Homework Help
Replies
4
Views
2K
Back
Top