Physics/Mechanics Equilibrium Force Question

In summary, the problem involves finding the reaction forces of A and B for a uniform bar with a mass of 100kg/m supported by a pin and a roller. The bar is at an angle of 60 degrees and is subject to a gravitational force of 9.81m/s2. The equations used are moment/torque = force*displacement, sum of MA=0, sum of FY=0, and sum of FX=0. The solution involves taking moments about point A and using the equations to solve for the reaction forces. However, the free body diagram at the left hand load is incorrect and further verification is needed. A diagram for the problem is available at the given link.
  • #1
bob29
18
0

Homework Statement


Find the reaction forces of A and B.
Uniform bar with a mass of 100kg/m supported by a pin and a roller.
[tex]\Theta[/tex] = 60
g=9.81m/s2
[URL]http://img340.imageshack.us/i/mechanicsproblem.jpg/[/URL]
[URL]http://img340.imageshack.us/i/mechanicsproblem.jpg/

Homework Equations


Moment/torque = Force*Displacement
Sum of MA=0 (moment about point A)
Sum of FY=0
Sum of FX=0

The Attempt at a Solution


Taking M about point A. (Counter-clockwise as +ve)
9BY - (1500N*7m) - (2400N*sin(60) * 3.5m) - [100kg/m*9m*9.81m/s2*(1/2*9m)]=0
9BY = 57,505N
BY = 6.389kN
B = 6.389kN​

Sum of FY=0
AY + BY - 2.4kN*sin(60) - 1.5kN - (W=8.829kN) = 0
AY = 6.018kN​

Sum of FX=0
AX - 2.4kN*cos(60) = 0
AX = 1.2kN​
Would like to verify whether my attempt at the question is correct, as well as my free body diagram.
 
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  • #2
A diagram for the question would help.
 
  • #3
Sorry, Iv'e just found the link to the figure. Your fbd is not correct at the left hand load. Something missing there. You can check your own work by taking moments about any point other than A.
 

FAQ: Physics/Mechanics Equilibrium Force Question

What is equilibrium in physics/mechanics?

Equilibrium in physics/mechanics refers to a state where all forces acting on an object are balanced, resulting in a net force of zero. This means that the object is either at rest or moving with a constant velocity.

How do you determine if an object is in equilibrium?

An object is in equilibrium if the sum of all forces acting on it is equal to zero. This can be determined by using Newton's first law of motion, which states that an object will remain at rest or in motion with a constant velocity unless acted upon by an external force.

What is the difference between static and dynamic equilibrium?

In static equilibrium, an object is completely at rest and there is no motion. In dynamic equilibrium, an object is moving with a constant velocity, but the net force is still equal to zero. This means that the object is experiencing balanced forces while in motion.

How do you calculate equilibrium force?

To calculate the equilibrium force, you need to first identify all the forces acting on the object and their respective magnitudes and directions. Then, you can use the equation F = ma (Newton's second law) to calculate the net force. If the net force is equal to zero, then the object is in equilibrium.

Can an object be in equilibrium if it is accelerating?

No, an object cannot be in equilibrium if it is accelerating. This is because acceleration is the result of an unbalanced force acting on the object. In equilibrium, the net force is equal to zero, so there can be no acceleration.

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