How Does Releasing an Object Affect Tension in a Pulley System?

Click For Summary
Releasing an object in a pulley system affects the tension in the rope due to the change in forces acting on the masses involved. When the first block (m1) is held in place, the tension is equal to the weight of the second block (m2). Upon releasing m1, the system experiences acceleration, resulting in a decrease in tension because the net force acting on m2 changes. The tension can be calculated using the equation T = M2*(g - a), indicating that tension is less when m2 is accelerating. Thus, the tension in the rope decreases when the first block is released, confirming that the tension is less than when the block was held.
Redfire66
Messages
36
Reaction score
0
So I've been thinking about something for some time now, suppose you have an object (m1) on a frictionless ramp. There is an ideal pulley where the object is attached to one another and hangs down off the ramp (m2). And suppose that someone is holding the first block in place (m1) . If the person stops holding onto it, the first block will be pulled by the second block (hence m2 > m1).
I heard that the tension should be less than before

From what I assume, the net force on the first object should be greater than the net force on the second object (to keep it in place, however they should not equal each other right? Since that could mean there is a velocity)
Anyhow, if the tension of the rope is affected by the second object pulling on it (m2) then shouldn't the tension be the same since releasing the object doesn't change the tension applied from the block pulling on it?
I have a diagram here, I assume that the tension on block 1 should be the same on block 2.
 

Attachments

  • Picture 1.png
    Picture 1.png
    3.2 KB · Views: 554
Physics news on Phys.org
I heard that the tension should be less than before.

That's correct. Consider the forces on mass M2 on it's own.

When stationary:
M2*g - T = 0
so
T = M2*g

When mass M2 is accelerating:
M2*g - T = M2*a
so
T = M2*(g - a)
which is less.

It might seem more obvious if you consider what happens if the rope is cut so that M2 is in freefall (a=g). Clearly T=0 which is less than M2*g.
 

Similar threads

  • · Replies 14 ·
Replies
14
Views
1K
  • · Replies 4 ·
Replies
4
Views
3K
  • · Replies 12 ·
Replies
12
Views
2K
  • · Replies 9 ·
Replies
9
Views
4K
  • · Replies 15 ·
Replies
15
Views
2K
Replies
5
Views
3K
  • · Replies 37 ·
2
Replies
37
Views
4K
Replies
46
Views
7K
  • · Replies 1 ·
Replies
1
Views
2K
Replies
16
Views
3K