# Homework Help: Achieve a state of static equilibrium

1. Mar 25, 2012

### Colin19

1. The problem statement, all variables and given/known data
If a body is acted upon by clockwise moments of 75 N at 1.25 m
And anticlockwise moments of 50 N at 1.3 m ,
Is it in a state of static equilibrium ?
If not what is required to achieve a state of static equilibrium ?

2. Relevant equations
sum of all forces on all particles of the system is zero ...

3. The attempt at a solution
Should I increase the 50 N to be 75 N , Then level the distance to get the equilibrium ?
I really don't know What/How to solve this , Please guide me through ,
Your helping efforts are Highly needed and appreciated .

2. Mar 25, 2012

### dikmikkel

That is one way, but i think the idea is to calculate the torque needed to obtain equilibrium, and since they act from different distances you would write something like:
$\sum\tau = l_1f_1 - l_2f_2 = 0$
and that is the condition /equation you need to solve it.

3. Mar 25, 2012

### Colin19

I don't get these symbols ? more HELP please
Please consider that I know so little, Teach me like a kid

4. Mar 25, 2012

### FeDeX_LaTeX

Do you know how to calculate a moment?

5. Mar 25, 2012

### Colin19

is it force x given distance ?
in the question it would be
75 N X 1.25 m
?

6. Mar 25, 2012

### FeDeX_LaTeX

Yes. The moment about a given point is the size of the force x the perpendicular distance to that point.

What do you know about the sum of the moments of the forces of a system that is in equilibrium?

7. Mar 25, 2012

### Colin19

8. Mar 26, 2012

### Colin19

- No it’s not in a state of static equilibrium,
In order for a body to be in static equilibrium
The vector sum of the forces and torques should be zero
Moments:
Moment = force × distance
Clockwise=
75N × 1.25m = 93.75 Nm .
Anticlockwise=
50N × 1.3m = 65 Nm.
Total moments= 93.75 – 65 = 28.75 N clockwise direction
so clearly it’s not in a state of static equilibrium,
If the perpendicular distance of the anticlockwise moment was changed to 1.875m we would then get
50N x 1.875 = 93.75
75N x 1.25 = 93. 75
We now have it in a state of static equilibrium.