Hydrostatics Problem

1. Nov 27, 2003

AngelofMusic

Hello,

I'm currently trying to solve a problem involving hydrostatics, but I'm getting stuck when it comes to drawing the forces in the FBD.

The original problem is here:

Diagram & Problem Info

This is my attempt at drawing the FBD:

My FBD

My calculations:

R(water) = 187.3 kN
R(mud) = 644.7 kN

I think that should be correct.

However, once I isolated the joint at the intersection of A,B, and C, there is no way I can get the joint to be in equilibrium. (See the bottom right corner of my FBD).

The same problem occurs at D, where the compression force in member D only goes up vertically, but I also have a horizontal component to the reaction force at D.

What am I doing wrong? Does anyone have any hints/suggestions on how to solve this?

Thanks a lot!

2. Nov 27, 2003

HallsofIvy

Staff Emeritus
You will need to assume that A and D are set in at their base (not hinged) so that they can support sideways forces.

3. Nov 27, 2003

AngelofMusic

Okay, so would the FBDs look something like this, then?

Second Attempt at FBD