How Does a Rope with Mass Affect the Forces on a Block?

  • Thread starter Thread starter JamesGold
  • Start date Start date
  • Tags Tags
    Block Mass Rope
Click For Summary
SUMMARY

The discussion centers on the dynamics of a block connected to a rope with mass, specifically addressing the forces acting on the block and the rope. The key equations referenced include Newton's second law, f = ma, which is critical for analyzing the forces. Participants express confusion regarding the free body diagrams of both the block and the rope, particularly how the tension varies along the length of the rope due to its mass. It is established that the tension force at the block's connection is different from the tension at the pulling end of the rope.

PREREQUISITES
  • Understanding of Newton's laws of motion, particularly f = ma.
  • Familiarity with free body diagrams and their application in physics.
  • Knowledge of tension forces in systems involving mass.
  • Concept of variable tension in ropes with mass.
NEXT STEPS
  • Study the effects of mass on tension in ropes using "Dynamics of Ropes with Mass".
  • Learn how to draw and interpret free body diagrams for complex systems.
  • Explore "Massless vs. Massive Ropes" to understand the differences in tension distribution.
  • Investigate "Pulley Systems with Mass" to apply concepts of tension and forces in practical scenarios.
USEFUL FOR

Students studying physics, particularly those focusing on mechanics, as well as educators seeking to clarify concepts related to forces and tension in systems involving mass.

JamesGold
Messages
39
Reaction score
0

Homework Statement



5OpuR.png


Homework Equations



f = ma

The Attempt at a Solution



I need help with all parts of this problem, but here are my comments on part a and c:

a) the block has its normal force vector pointing up and its weight vector pointing down. the tension of the rope is pulling it to the right. I'm very confused about the rope's free body diagram.

c) Why should the magnitude of the force that the rope exerts on the block be any different from the magnitude of the force pulling the rope to the right?
 
Physics news on Phys.org
JamesGold said:

Homework Statement



5OpuR.png


Homework Equations



f = ma

The Attempt at a Solution



I need help with all parts of this problem, but here are my comments on part a and c:

a) the block has its normal force vector pointing up and its weight vector pointing down. the tension of the rope is pulling it to the right.
Yes , but the rope tension is variable. When drawing a free body diagram of the block alone, the tension force is the rope tension at the connection to the block.
I'm very confused about the rope's free body diagram.
which is not the same as the block's free body diagram. The rope has mass. Isolate the full length of rope. F - Tmin[/color] = m_r(a)
c) Why should the magnitude of the force that the rope exerts on the block be any different from the magnitude of the force pulling the rope to the right?
Because in this problem, the rope has mass . The rope tension is F only at the pulling end. It is smaller[/color] at the other end where it attaches to the block.
For starters, answer part b first, looking at the rope/block system.
 
Last edited:
JamesGold said:

Homework Statement



5OpuR.png


Homework Equations



f = ma

The Attempt at a Solution



I need help with all parts of this problem, but here are my comments on part a and c:

a) the block has its normal force vector pointing up and its weight vector pointing down. the tension of the rope is pulling it to the right. I'm very confused about the rope's free body diagram.

c) Why should the magnitude of the force that the rope exerts on the block be any different from the magnitude of the force pulling the rope to the right?

You are probably more familiar with problems using a massless [light] string.

To get a feel for this situation, you might like to replace the heavy string, with a light one BUT with a mass added in the middle of the string. - pulling two masses tied together if you like.
 

Similar threads

  • · Replies 38 ·
2
Replies
38
Views
5K
Replies
4
Views
993
  • · Replies 10 ·
Replies
10
Views
3K
Replies
2
Views
1K
  • · Replies 25 ·
Replies
25
Views
6K
Replies
6
Views
4K
  • · Replies 13 ·
Replies
13
Views
3K
  • · Replies 14 ·
Replies
14
Views
2K
Replies
11
Views
3K
Replies
5
Views
8K