Crazy Pulley Problem: Solve for Distance, Acceleration & Tension

Click For Summary

Homework Help Overview

The problem involves a system of two blocks connected by a massless string over a pulley, with one block sliding on a frictionless surface and the other hanging. The task is to find the horizontal distance moved by the sliding block, its acceleration, and the tension in the string, given specific masses and gravitational acceleration.

Discussion Character

  • Mixed

Approaches and Questions Raised

  • Participants discuss drawing free-body diagrams for both masses to analyze the forces acting on them. There is mention of a relationship between the accelerations of the two masses, with some suggesting one may be twice the other. Questions arise regarding the forces acting on the mass on the table and the role of tension in the system.

Discussion Status

Participants are exploring different aspects of the problem, including the forces acting on each mass and the implications of the pulley system. Some have provided insights into the tension in the string and how it relates to the forces on the blocks, but no consensus has been reached on the overall approach to the problem.

Contextual Notes

There is a focus on the assumption that the pulleys are massless and frictionless, which influences the tension throughout the string. Participants are also grappling with the relationship between distance and acceleration in the context of the problem.

spursfan2110
Messages
19
Reaction score
0

Homework Statement



Part 1:

A 17 kg block with a pulley attached slides along a frictionless surface. It is connected by a massless string to a 5.9 kg block via the arrangement shown (attached below). The acceleration of gravity is 9.81 m/s/s. Find the horizontal distance the 17 kg block
moves when the 5.9 kg block descends a distance of 9.3 cm. The pulleys are massless and
frictionless. Answer in units of cm.

Part 2:

Find the acceleration of the 17 kg block. Answer in units of m/s/s.

Part 3:

Find the tension in the connecting string. Answer in units of N.

Homework Equations



F = ma



The Attempt at a Solution



I am absolutely stumped on all three...I don't want someone to solve this for me, but any little hint to get me started would be great. My main problem is that none of the equations I have have anything to do with distance and so I don't know how to relate that to these forces and acceleration.
 

Attachments

Last edited:
Physics news on Phys.org
Draw a free-body diagram of the two masses of interest. Note that there is a relationship between accelerations of the two masses, I think one is twice the other.
 
Ok, I've drawn the diagram for the hanging mass, and with T being an upward force and mg being a downward force, ma being mg -T, but I am really confused about the mass on the table. Gravity and the normal force cancel each other out obviously, and are there two tension forces acting on it as well?
 
Since single string is connecting the two masses, the tension is each segment of the string must be equal.
So m2*a = ...? Here m2 = 17 kg
 
Since the first pulley(the smaller one) is physically connected to the first block, you have to treat the pulley as being a part of the block. So the force experienced by the (block+small pulley) is 2T while the tension force in the other block is only T. Remember that tension in the string is the same throughout since all pulleys are said to be massless and frictionless.
2T = 17 a
and
5.9*g - T = 5.9*a
 

Similar threads

  • · Replies 3 ·
Replies
3
Views
2K
Replies
15
Views
2K
  • · Replies 12 ·
Replies
12
Views
1K
  • · Replies 2 ·
Replies
2
Views
2K
Replies
4
Views
913
  • · Replies 27 ·
Replies
27
Views
3K
  • · Replies 47 ·
2
Replies
47
Views
3K
  • · Replies 22 ·
Replies
22
Views
2K
  • · Replies 10 ·
Replies
10
Views
1K
  • · Replies 15 ·
Replies
15
Views
6K