Static Equilibrium: Homework Questions

In summary, the conversation discusses the concept of torque and rotational dynamics, specifically in relation to a problem involving normal forces and pivot points. The first part addresses the question of whether there should be a separate normal force for each hand in part a of the problem, and why the torque for Fn1h is not equal to zero in part b. The conversation then delves into the concept of pivot points and how they are used in calculations, with a reference to problems involving beams between two supports. The conversation ends with a suggestion to look at a specific resource for a better understanding of the topic and a question about the person's familiarity with levers.
  • #1
Speedking96
104
0

Homework Statement


I have a question about the following question:

upload_2014-12-15_20-2-23.png


Firstly, shouldn't there be a normal force for each hand (part a), but here they treat it as one normal force.

Also in part b, why isn't the torque for Fn1h = 0? Since that is the pivot point, isn't the moment arm zero?
 
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  • #2
Firstly, shouldn't there be a normal force for each hand (part a), but here they treat it as one normal force.
How is the result different if you give each hand a separate normal force?

Also in part b, why isn't the torque for Fn1h = 0? Since that is the pivot point, isn't the moment arm zero?
##F_{N1} \neq 0## and ##h\neq 0## therefore ##F_{N1}h \neq 0## ... take a closer look: what are they using for the pivot point in that calculation?
 
  • #3
Wow. The pivot point is the location of the foot and N1 is for the hands. I see. Thank you.
 
  • #4
Well done. Remember all those horizontal mean static problems - beam between two supports?
Remember how you'd do a sum-of-torques for each support as the pivot?
 
  • #5
I actually don't know what you're referring to as I am learning torque and rotational dynamics on my own (on my final exam tomorrow and my teacher rushed everything on rotation ) - I don't think I've come across a problem like that
 
  • #6
Have a look at:
http://www.pstcc.edu/departments/natural_behavioral_sciences/Web%20Physics/Experiment%2002-1320.htm
... it counts as essential physics.

Have you done levers?
 

What is static equilibrium?

Static equilibrium refers to a state in which an object is at rest and all forces acting on it are balanced. This means that there is no net force or torque acting on the object, so it remains in a stable position.

How do you calculate the forces in static equilibrium?

In order to calculate the forces in static equilibrium, you must use Newton's first and second laws. This involves setting up a free body diagram and applying the equations ΣF=0 and Στ=0 to determine the magnitude and direction of the forces and torques acting on the object.

What are the conditions for static equilibrium?

The conditions for static equilibrium are that the sum of all forces acting on the object must be equal to zero, and the sum of all torques (rotational forces) acting on the object must also be equal to zero. This means that the object is not accelerating or rotating.

How do you know if an object is in static equilibrium?

If an object is in static equilibrium, it will remain at rest and not move or rotate. Additionally, the sum of all forces and torques acting on the object will be equal to zero. If any of these conditions are not met, then the object is not in static equilibrium.

What are some real-life examples of static equilibrium?

Some examples of real-life static equilibrium include a book resting on a table, a ladder leaning against a wall, and a suspension bridge. In each of these situations, the forces and torques acting on the object are balanced, resulting in a stable position.

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