Mechanics - massive pulley, Atwood machine or similar

In summary, a massive pulley can cause differences in tension in a length of cable due to factors such as friction in the wheels, constant velocity situations, and acceleration. These differences in tension can also occur during periods of jerk where the rate of force change travels at the speed of sound through the cable. If the mass of the cable is ignored, then this effect is not present.
  • #1
iloveannaw
45
0
hi,

why does a massive pulley cause different tensions in a length of cable? I've looked for answers but got only that "the pulley needs to be lifted". Couldn't really picture it. Some maths would be nice :smile:

cheers!
 
Last edited:
Physics news on Phys.org
  • #2
It would seem that differences in tension would require friction in the wheels in a constant velocity situation. You could also have differences in tension during periods of jerk where the rate of force change travels as the speed of sound through the cable.

In the case of acceleration, imagine that the cable is a single length of cable in space, and being pulled at one end to accelerate it. The amount of tension will be highest at the pulled end and lowest at the free end. If you ignore the mass of the cable, then this effect does not exist.
 

1. What is a massive pulley in mechanics?

A massive pulley is a type of pulley that has a significant amount of mass compared to the objects it is supporting. This can affect the dynamics of the system and may introduce additional forces such as tension and friction.

2. How does an Atwood machine work?

An Atwood machine is a simple mechanical device consisting of two masses connected by a string or rope that passes over a pulley. The machine utilizes the force of gravity to create a net force that causes the masses to accelerate towards each other or away from each other.

3. What are the key principles of mechanics that apply to massive pulleys and Atwood machines?

The key principles of mechanics that apply to these systems are Newton's laws of motion, which describe how forces affect the motion of objects, and the principle of conservation of energy, which states that energy cannot be created or destroyed, only transferred or converted.

4. How does the mass of a pulley affect the dynamics of a system?

The mass of a pulley can affect the dynamics of a system in several ways. First, it can contribute to the total mass of the system, which affects the acceleration of the masses. Additionally, a massive pulley may introduce additional forces such as tension and friction, which can affect the overall motion of the system.

5. Are there any real-world applications of massive pulleys or Atwood machines?

Yes, there are many real-world applications of these mechanical systems. For example, massive pulleys are commonly used in elevators and cranes to lift heavy loads. Atwood machines are used in weightlifting equipment, where the force of gravity is used to provide resistance for strength training. They are also used in some types of clocks and timers.

Similar threads

Replies
31
Views
3K
Replies
17
Views
4K
  • Mechanics
Replies
3
Views
2K
Replies
4
Views
2K
  • Mechanics
Replies
7
Views
3K
  • Introductory Physics Homework Help
Replies
10
Views
3K
  • Introductory Physics Homework Help
Replies
17
Views
1K
Replies
1
Views
2K
  • Introductory Physics Homework Help
Replies
8
Views
2K
Back
Top