How to find the the acceleration of the block M?

Click For Summary

Homework Help Overview

The problem involves finding the acceleration of a block of mass M in a frictionless environment, with multiple blocks and forces acting on them. The discussion revolves around the relationships between tensions, gravitational forces, and the accelerations of the blocks involved.

Discussion Character

  • Mixed

Approaches and Questions Raised

  • Participants explore various equations relating tension and gravitational forces, questioning the cancellation of acceleration terms. There is discussion about the correct identification of which block's acceleration is denoted by the variable a, and whether the accelerations of the blocks are the same.

Discussion Status

The discussion includes attempts to clarify the relationships between the blocks' accelerations and the forces acting on them. Some participants suggest corrections to previous assumptions, while others express confusion about the implications of these corrections. There is no explicit consensus on the final answer, but some guidance has been offered regarding the relationships between the blocks.

Contextual Notes

Participants are working under the assumption that all surfaces are frictionless, and there is a mention of a specific angle (30 degrees) affecting the forces involved. The original poster's initial equations are being scrutinized for accuracy and relevance.

avistein
Messages
48
Reaction score
1
1.Homework Statement
Find the acceleration of the block of mass M in the situation shown.All surfaces are frictionless

2.The attempt at a solution
2Mg-2T=2Ma
T=Mg-Ma
and T-mgsin30=ma

But a is canceled .what to do?
 

Attachments

  • masspulleysystem2.JPG
    masspulleysystem2.JPG
    6.1 KB · Views: 515
Last edited:
Physics news on Phys.org
T=Mg-Ma

Mg-Ma-Mgsin30=Ma

2Ma = 1/2 Mg
a= 1/4 g

Not cancelled?
 
Sorry, but answer given is g/3.
 
Acceleration of which block is denoted by ##a##? Are the accelerations the same for both blocks?
 
  • Like
Likes   Reactions: 1 person
voko said:
Acceleration of which block is denoted by ##a##? Are the accelerations the same for both blocks?

Oh,sorry.the acceleration of block 2M is a ,so acceleration of M is 2a.
 
Do you get the answer with that correction?
 
voko said:
Do you get the answer with that correction?

Yes sir,after Bvu's help,it is solved.
 
Last edited:
Don't understand. In the expression T-Mgsin30=Ma a is clearly the acceleration of block M, which is what is asked for. So keep it and change the acceleration of the other block to a/2, like:

(2M)g - 2T= (2M) (a/2). Bingo!
 
  • Like
Likes   Reactions: 1 person

Similar threads

Finding acceleration of the pulley block system
  • · Replies 23 ·
Replies
23
Views
3K
What are the accelerations in the multiple-pulley problem?
  • · Replies 10 ·
Replies
10
Views
3K
Newton's law problem: Pushing 2 stacked blocks on a horizontal table
  • · Replies 13 ·
Replies
13
Views
3K
Calculating acceleration of a prism and block connected to a wall through a rope and pulley
  • · Replies 4 ·
Replies
4
Views
1K
Find acceleration of Moving incline with a block on it
  • · Replies 11 ·
Replies
11
Views
3K
Block of mass M attached to rope of mass m
  • · Replies 10 ·
Replies
10
Views
3K
Tension force and acceleration Problem
  • · Replies 1 ·
Replies
1
Views
2K
Finding the work done by a block
  • · Replies 4 ·
Replies
4
Views
3K
Acceleration of a Block Sliding Down a Wedge
  • · Replies 3 ·
Replies
3
Views
1K
Sliding block hits and compresses a spring
  • · Replies 5 ·
Replies
5
Views
1K