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@Gyro Gearloose
Note for OP
+solved @user1 @user2... to close the thread when your doubt is solved. Mention the users who helped you solve the doubt. This will be added to their stats.Is the answer 12?
@SirLancelotDuLac
Ye
Can you share your working?
F=ma along horizontal and vertical
How do we know if the system is not accelerating towards the left of right?
For instance in this, the force on the lighter block would be 60-(T=)12-43.2 which is not zero
Net force on the system along horizontal is zero, so net acceleration must also be zero
Friction takes care of that.
Wait is this leading to the paradoxical "Friction or Tension" question?
Like which one acts first, friction or tension?
That would be friction, but in this case, it's irrelevant.
Normal>friction>tension>spring in terms of response speed iirc
For instance for T=60 we would have block having no tendency to move, which would make the frinction zero
We don't need to know the priority here though, since we can take equilibrium along horizontal.
Because net force is zero
Well, 2 questions:
1. What if the frictions of the two blocks come out to be different? In that case there can be a net acceleration of the system.
2. Can tension act first than friction?
wait with changing time wont friction change
The first one is something I need to work out actually. Oops.
Second one is simple. Yes, but only if tension is the cause and friction is the effect. If they are both responses to a single cause, then friction is first.
But our question says na that it is accelerating in upwards and no mention of any acceleration of x axis and then there is the different coefficient of friction
"the surface is accelarating upwards" tho.
Yeah thts the acceleration on y axis
Wierd. I remember reading about this paradox somewhere. Lemme search once.
Surface is our platform where it is kept
ok wait nvm i get
Ah, the question maybe ambigous ig. For an infinitisemaly small displacement of block the value of friction and tension would change if at equillibrium.
Why did you consider that maximum static friction would be applied over the block?
I had once got into this confusion while solving a question, and I didn't clear it out yet.
The friction v tension one?
Yes
It was a question like a block attached to a pulley over a rough surface of an inclined plane
I too have the same confusion here in this question as well, why will we consider maximum friction being applied?
but if tension is 12 net force of right block will be 60-T-umg = 19.2 towards right
this would mean block on left reaches limiting friction while the one on right doesnt
why doesnt the inverse happen
but coeff is diff for the blocks
so how do we know theres horiz equilibrium
hey are you sure the answer given is 12? according to my teacher it is 16.8
The answer key maybe wrong as plenty of other questions were wrong too.
But can you share your approach?
i didnt fully understand but ill quote what he said:
The external forces are cancelling each other, so yes system will be in equilibrium.
As the external force keeps increasing, it'll first reach the value of 43.2N which is the maximum fiction on the 6 KG block. After this tension will become non-zero to balance the extra force. So ultimately the tension will have to be 60-43.2 which is 16.8 Ν.
Ah, the equillibrium point is clear now. But wouldn't that just give that the friction in both the blocks is same, just in different directions?
yes..until 6kg block reaches maximum friction. then tension will generate to keep equilibrium. that was my understanding
Aah I see.
Thanks a lot.
+solved @idk either @Opt
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