I The direction of three forces acting on a line has to be concurrent?

  • I
  • Thread starter Thread starter Jason Ko
  • Start date Start date
  • Tags Tags
    Direction Forces
AI Thread Summary
In a system in equilibrium, if the third line of action does not intersect the crossing point of two force lines, a net torque is created, which contradicts the conditions for equilibrium. The discussion highlights the importance of understanding the proof provided in the textbook regarding this concept. Participants acknowledge a lack of initial comprehension but express agreement with the established principles. The exchange emphasizes the necessity of careful reading and comprehension in physics discussions. Understanding these fundamental concepts is crucial for grasping equilibrium conditions.
Jason Ko
Messages
21
Reaction score
6
TL;DR Summary
I found this theorem in D. Morin's book on mechanics. How to prove it mathematically? Does it have a name?
1709042028580.jpeg
 
Physics news on Phys.org
Take the point of crossing of two of the force lines of action. If the third line of action does not pass through that crossing, there is a net torque and therefore this cannot happen for a system in equilibrium.
 
Thanks! I was being stupid
 
Jason Ko said:
Thanks! I was being stupid
Probably you didn't read the "simple" proof provided below the statement that you highlighted in the textbook.
 
kuruman said:
Probably you didn't read the "simple" proof provided below the statement that you highlighted in the textbook.
Nor I. Good thing I agree with Morin though … 😛
 
Thread 'Gauss' law seems to imply instantaneous electric field'

Thread 'Gauss' law seems to imply instantaneous electric field'

Imagine a charged sphere at the origin connected through an open switch to a vertical grounded wire. We wish to find an expression for the horizontal component of the electric field at a distance ##\mathbf{r}## from the sphere as it discharges. By using the Lorenz gauge condition: $$\nabla \cdot \mathbf{A} + \frac{1}{c^2}\frac{\partial \phi}{\partial t}=0\tag{1}$$ we find the following retarded solutions to the Maxwell equations If we assume that...
View full post »

Thread 'Off resonance driving of a MW/RF cavity'

Hello! Let's say I have a cavity resonant at 10 GHz with a Q factor of 1000. Given the Lorentzian shape of the cavity, I can also drive the cavity at, say 100 MHz. Of course the response will be very very weak, but non-zero given that the Loretzian shape never really reaches zero. I am trying to understand how are the magnetic and electric field distributions of the field at 100 MHz relative to the ones at 10 GHz? In particular, if inside the cavity I have some structure, such as 2 plates...
View full post »

Similar threads

B Understanding Newton's Third Law and the Net Force on Objects
Replies
10
Views
276
B Determine forces acting on double inclined plane
Replies
13
Views
2K
I Directional magnetic field
Replies
9
Views
1K
B Normal force in case of inclined plane and banked turn
Replies
3
Views
2K
I Distributed Forces and force density....
Replies
8
Views
3K
B Forces on a passenger in a car?
Replies
7
Views
3K
B What forces act on a bar when you do pull-ups?
Replies
5
Views
2K
I Is it accurate to say work is motion against an opposing force?
2
Replies
75
Views
4K
B Electric Field Direction: Are We Assuming a Universal Positive Frame?
Replies
20
Views
1K
B Would there be any varying forces acting on individual wells in rotation? (stir/shaker plate)
Replies
9
Views
957

Hot Threads

Recent Insights

Back
Top