Pulley system -- Calculate the mass that balances this pulley system

Click For Summary
The discussion focuses on calculating the mass that balances a pulley system, with an emphasis on understanding the free body diagram. The user has calculated the force exerted by mass A but struggles with the tension in the rope and its variation. Clarification is sought on the tension forces acting on both masses A and B. Participants suggest working symbolically throughout the calculations to simplify the process and avoid unnecessary arithmetic. The conversation highlights the importance of accurately representing forces in a free body diagram for solving pulley problems.
FFTB
Messages
1
Reaction score
0
Homework Statement
Calculate the mass of mB that makes the system to be in equilibrium. Neglect the possible friction
Relevant Equations
Sin cos tan
pulley.png

I've been stuck at this pulley system for a while.
I've calculated the force of which A pulls => FA = sin25*50*9.82 = 208.5 N
But I get stuck on the free body diagram.
Can someone help and explain the freebody diagram
uträkning.png
 

Attachments

  • pulley.png
    pulley.png
    4.3 KB · Views: 159
Physics news on Phys.org
Let T be the tension in the rope. Does it vary along the rope? What is the tension force on mass A? On mass B?
 
Your work looks ok except for ##m_B=T##. What have you missed out?
As a matter of style, learn to work entirely symbolically, only plugging in numbers at the end. It has many advantages.
In the present case, you could have avoided some arithmetic since g would cancel.
 

Thread 'Magnitude of buoyant force in fluids of different densities'

The book claims the answer is that all the magnitudes are the same because "the gravitational force on the penguin is the same". I'm having trouble understanding this. I thought the buoyant force was equal to the weight of the fluid displaced. Weight depends on mass which depends on density. Therefore, due to the differing densities the buoyant force will be different in each case? Is this incorrect?
View full post »

Similar threads

Pulley system problem: 6 Pulleys and 1 Mass
  • · Replies 5 ·
Replies
5
Views
1K
System of two pulleys and three masses
  • · Replies 22 ·
Replies
22
Views
6K
Experimental Design: Pulley and Mass Hangers
  • · Replies 30 ·
2
Replies
30
Views
3K
Force applied on the pulley of a system
  • · Replies 8 ·
Replies
8
Views
3K
Explain friction in a pulley system
  • · Replies 13 ·
Replies
13
Views
7K
Calc Forces on Pulleys: 200N, 300N Masses, No Friction
  • · Replies 1 ·
Replies
1
Views
2K
Acceleration of a mass lowered by a motor (Help with Non-Ideal Pulley)
  • · Replies 4 ·
Replies
4
Views
2K
Motion of a system that has two masses and three pulleys
  • · Replies 11 ·
Replies
11
Views
2K
Time period of SHM & Energy conservation in pulley-spring-block system
  • · Replies 24 ·
Replies
24
Views
3K
Pulley system, find the acceleration and tension
  • · Replies 40 ·
2
Replies
40
Views
6K