Forces on two different blocks with two pulleys

In summary: Rather, the two accelerations are related by the fact that the velocity of m2 is slower than the velocity of m1.No. The forces on the objects are not related in any such way.
  • #1
Amphibia
6
1
Homework Statement
Question 12
Relevant Equations
Scalar equations
I don't know what to do as I know the forces acting on it but not the scalar like I just don't understand the question with two different pulleys I know the tension same everywhere
20220321_231155.jpg
 
Physics news on Phys.org
  • #2
Welcome!
How would you apply what you have studied about forces and masses and accelerations to this problem?
Don't let those pulleys confuse you.
 
  • #3
Lnewqban said:
Welcome!
How would you apply what you have studied about forces and masses and accelerations to this problem?
Don't let those pulleys confuse you.
Well the forces in fnetx and fnety the m1 fnety is 0 so there's fnetx and Ft-Ff for the m1 fnetx and m2 has fnetx=0 and the Fnety is Ft-Fg my only known is gravity
 
  • #4
Amphibia said:
Well the forces in fnetx and fnety the m1 fnety is 0 so there's fnetx and Ft-Ff for the m1 fnetx and m2 has fnetx=0 and the Fnety is Ft-Fg my only known is gravity
If all Fnet's are zero, there is no movement or acceleration.
But the wording of the problem suggests that there is certain acceleration, and nothing is told about coefficient of friction.
 
  • #5
Lnewqban said:
If all Fnet's are zero, there is no movement or acceleration.
But the wording of the problem suggests that there is certain acceleration, and nothing is told about coefficient of friction.
Oh so there's no friction the objects are stationary and m1 and m2 are the same masses or I think m1 is = to more than the tension
 
  • #6
Nothing suggests that m1 and m2 are the same masses.
I believe that you can assume that there is no friction force between m1 and the flat surface, that the string is non-extensible and that the pulleys are massless and free of friction at their pivots.

Then, the weight of m2 is not balanced by any other force and it should induce acceleration of the whole system (m1 and m2).

However, m1 and m2 can't move at the same velocity, and that should be considered and the forces acting on each should be analyzed by free-body diagrams of each mass.
 
  • #7
Lnewqban said:
Nothing suggests that m1 and m2 are the same masses.
I believe that you can assume that there is no friction force between m1 and the flat surface, that the string is non-extensible and that the pulleys are massless and free of friction at their pivots.

Then, the weight of m2 is not balanced by any other force and it should induce acceleration of the whole system (m1 and m2).

However, m1 and m2 can't move at the same velocity, and that should be considered and the forces acting on each should be analyzed by free-body diagrams of each mass.
Ok so what I see now is that they don't have the same acceleration, the rope is a constant that doesn't extend, velocity is different, the masses are different and that I only see related are the normal force and the tension force of each other
 
  • Like
Likes Lnewqban
  • #8
Amphibia said:
they don't have the same acceleration
Right, but what is the relationship between the two accelerations?
 
  • #9
haruspex said:
Right, but what is the relationship between the two accelerations?
That both of their fnet are the same or they have the same amount of forces on each other
 
  • #10
Amphibia said:
That both of their fnet are the same or they have the same amount of forces on each other
No. The forces on the objects are not related in any such way.

Rather than guessing, start by drawing the free body diagrams for each mass. Then ask yourself what information you get out of that and what information you get from the string being inextensible.
 
  • #11
Amphibia said:
That both of their fnet are the same or they have the same amount of forces on each other
The relationship is kinematic, nothing to do with forces.
 

1. What is the purpose of using two pulleys in a system with two blocks?

The purpose of using two pulleys in a system with two blocks is to change the direction of the force applied to the blocks. This allows for a more efficient transfer of force and can also change the magnitude of the force.

2. How do you calculate the net force on each block in a system with two pulleys?

To calculate the net force on each block, you must first determine the individual forces acting on each block. Then, you can use Newton's Second Law (F=ma) to calculate the net force by adding up all the individual forces acting on the block.

3. What factors affect the forces on the two blocks in a system with two pulleys?

The forces on the two blocks in a system with two pulleys can be affected by several factors, including the mass of the blocks, the angle of the pulleys, and the tension in the ropes or cables connecting the blocks to the pulleys.

4. Can the forces on the two blocks ever be equal in a system with two pulleys?

Yes, it is possible for the forces on the two blocks to be equal in a system with two pulleys. This can occur if the mass of the blocks is equal, the angle of the pulleys is equal, and the tension in the ropes or cables is equal.

5. How does friction affect the forces on the two blocks in a system with two pulleys?

Friction can affect the forces on the two blocks in a system with two pulleys by reducing the magnitude of the force. Friction is a resistive force that acts in the opposite direction of motion, so it can decrease the overall force applied to the blocks.

Similar threads

  • Introductory Physics Homework Help
Replies
2
Views
598
  • Introductory Physics Homework Help
Replies
23
Views
1K
  • Introductory Physics Homework Help
3
Replies
102
Views
4K
  • Introductory Physics Homework Help
Replies
17
Views
1K
  • Introductory Physics Homework Help
Replies
1
Views
2K
  • Introductory Physics Homework Help
Replies
10
Views
3K
  • Introductory Physics Homework Help
Replies
7
Views
256
  • Introductory Physics Homework Help
Replies
5
Views
793
  • Introductory Physics Homework Help
2
Replies
35
Views
2K
  • Introductory Physics Homework Help
Replies
18
Views
1K
Back
Top