- #1
Force at Pipe Bend Outlet A: 0.0707(12cos120 - 12)
Click For Summary
Homework Help Overview
The discussion revolves around the calculation of forces at the outlet of a pipe bend, specifically addressing the force at outlet A and its relation to the angle of 120 degrees with the horizontal. Participants are examining the definitions and directions of forces acting on the water and the pipe bend.
Discussion Character
- Conceptual clarification, Assumption checking, Problem interpretation
Approaches and Questions Raised
- Participants are questioning the validity of the force expression at outlet A and discussing the implications of the angle involved. There are inquiries about the definitions of forces (Fx and Fy) and whether they should represent the force acting on the water by the pipe bend or vice versa. Some participants are exploring how to define resultant forces and the impact of changing these definitions on calculations.
Discussion Status
The discussion is ongoing, with participants providing insights into the definitions of forces and their directions. There is a recognition that different approaches can yield the same results if the definitions are consistently applied. However, there is no explicit consensus on the best approach to take.
Contextual Notes
Participants are referencing specific figures and attachments related to earlier problems, which may be causing confusion regarding the correct setup for the current problem. There is also a mention of the need to clarify the definitions used in the context of the problem.
- #2
- 42,893
- 10,527
I think one of your attachments ('127') is for an earlier problem.foo9008 said:
- #3
- #4
- 42,893
- 10,527
You are confusing yourself. Both 126 and 127 were for an earlier problem. Neither has an angle 120 degrees in it. Only 128 matches the text of your post in this thread.foo9008 said:
- #5
- #6
- 42,893
- 10,527
No, the correct two images are 128 and 129.foo9008 said:
Again you are right. But if you look at the next line the correct numerical value is obtained.foo9008 said:
- #7
foo9008
- 676
- 4
haruspex said:
why Fx means the force of blade acts on water ? shouldn't it be force of water act on blade?haruspex said:
- #8
- 42,893
- 10,527
The author has chosen to define Fx and Fy as forces from the blade acting on the water.foo9008 said:
- #9
foo9008
- 676
- 4
if i want to directly find the resultant force acting on the pipe bend on the water , how to find it ? what's the equation ?haruspex said:
- #10
- 42,893
- 10,527
I'm not sure what you are asking. If you mean, how to find force of water on blade, just define Fx and Fy in the opposite directions.foo9008 said:
If you mean how to find the resultant force without finding the x and y components, define your axes to be aligned with and perpendicular to the resultant, which is at some unknown angle theta to the incoming water. Then find the components of various lnown forces in those directions. It is just as much work, though.
- #11
foo9008
- 676
- 4
i mean find the resultant force acting on the pipe bend by the water , can we define Fx = resultant force acting on the pipe bend by the water instead ofharuspex said:
resultant force acting on the water by the pipe bend ? so , if we define Fx = resultant force acting on the pipe bend by the water, then Fx = 0.0707(12cos 120 -12) +0.1414(12 cos60 -12 ) = 2.12KN(to the left)
is it correct to do so ?
i just couldn't understand why the author define Fx as resultant force acting on water by the pipe bend ?
- #12
- 42,893
- 10,527
Sure, you can define it the other way round. It just flips its sign in every equation.foo9008 said:
- #13
foo9008
- 676
- 4
Why we can't just not flip the equation and do as in the notes, but define fx as force acting on the bend by the water? I don't understand why the author define fx as force acting on the water by bend and do it this wayharuspex said:
- #14
- 42,893
- 10,527
I can't think of a reason.foo9008 said:
Similar threads
- · Replies 26 ·
- · Replies 2 ·
- · Replies 3 ·
- · Replies 3 ·
- · Replies 14 ·
- · Replies 7 ·