Statics, Stress, and Machine design

[jmm21242]

Homework Statement

I have attached a copy of the assignment problem. I have been having serious trouble finding the value of the force P. I know the equations to use for part b and c but I need to know the force P to complete the rest of the problem.

Homework Equations

a) The problem tells me that the object is in equilibrium so I know that the summation of the forces in the x and y direction are zero.
\SigmaF(x)=0=F_c-P
\SigmaF(y)=0=F_c-15kN-50kN

I don't know what other equations I can derive from this to help me solve for P

b) I know that to find the minimum diameter of the rod AB i will use the equation:
Safety Factor=stress to failure/stress allowed=>600 MPa/(F_max/Area)

From here I can derive the value of the diameter of the rod if I know the value of P

c) I believe that part c is the same equation as part b please let me know if I am wrong on this.

The Attempt at a Solution

I would try and make an attempt but I can not make an attempt mathematically without first knowing how to do part A. I understand the equations for part b and c but do not know how I would solve to force P.

 

[PhanthomJay]

Homework Statement

I have attached a copy of the assignment problem. I have been having serious trouble finding the value of the force P. I know the equations to use for part b and c but I need to know the force P to complete the rest of the problem.

Homework Equations

a) The problem tells me that the object is in equilibrium so I know that the summation of the forces in the x and y direction are zero.
\SigmaF(x)=0=F_c-P
\SigmaF(y)=0=F_c-15kN-50kN

I don't know what other equations I can derive from this to help me solve for P

b) I know that to find the minimum diameter of the rod AB i will use the equation:
Safety Factor=stress to failure/stress allowed=>600 MPa/(F_max/Area)

From here I can derive the value of the diameter of the rod if I know the value of P

c) I believe that part c is the same equation as part b please let me know if I am wrong on this.

The Attempt at a Solution

I would try and make an attempt but I can not make an attempt mathematically without first knowing how to do part A. I understand the equations for part b and c but do not know how I would solve to force P.

Watch subscripts when looking in x and y directions, P = Fcx and Fcy is 65. Then you want to look at the 3rd equilibrium equation, sum of moments about C (or any point) = 0.

Once you now solve for Fc using Pythagorus, the pin is in double shear...