How To Find The Drag and Lift Force?


by mymachine
Tags: drag, force, lift
mymachine
mymachine is offline
#1
Feb6-13, 09:39 AM
P: 42
How can I find the drag and lift force such as below illustration?

http://s4.postimage.org/sxmnflttp/dragillustration.png

Below is my calculation:

http://s4.postimage.org/ao75d6r0d/dragcalculation.png
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jedishrfu
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#2
Feb6-13, 10:05 AM
P: 2,491
I dont understand how is drag and lift related to a sliding block?
mymachine
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#3
Feb6-13, 12:08 PM
P: 42
Quote Quote by jedishrfu View Post
I dont understand how is drag and lift related to a sliding block?
It's not a sliding block.

It's moving on the air.

berkeman
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#4
Feb6-13, 12:33 PM
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How To Find The Drag and Lift Force?


Quote Quote by mymachine View Post
How can I find the drag and lift force such as below illustration?

http://s4.postimage.org/sxmnflttp/dragillustration.png

Below is my calculation:

http://s4.postimage.org/ao75d6r0d/dragcalculation.png
Quote Quote by mymachine View Post
It's not a sliding block.

It's moving on the air.
Which block? There are two in the illustration. And which way is it moving? Where does this problem come from?
Travis_King
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#5
Feb6-13, 12:39 PM
P: 764
Perhaps the illustration is showing that the block has a rectangular cross-section? Then, perhaps the block is moving to the right, in which case the 2000 N is the drag force?

I have never ever seen an FBD like this for fluid/aero dynamics...
mymachine
mymachine is offline
#6
Feb6-13, 12:53 PM
P: 42
Quote Quote by berkeman View Post
Which block? There are two in the illustration. And which way is it moving? Where does this problem come from?
Two?

Wrong.

As you can see from the first image, the "A" is the area of the surface which its depth is 10 m.

The motion is from right to left.

The snout is at the front and the flat is at the back.
jedishrfu
jedishrfu is offline
#7
Feb6-13, 12:55 PM
P: 2,491
Quote Quote by mymachine View Post
Two?

Wrong.

As you can see from the first image, the "A" is the area of the surface which its depth is 10 m.

The motion is from right to left.

The snout is at the front and the flat is at the back.
Be nice, we're trying to help and you didn't provide enough information to begin with.
mymachine
mymachine is offline
#8
Feb6-13, 12:59 PM
P: 42
Quote Quote by jedishrfu View Post
Be nice, we're trying to help and you didn't provide enough information to begin with.
Am I that really not so nice?

I just telling that was wrong.

No other purpose.
jedishrfu
jedishrfu is offline
#9
Feb6-13, 01:05 PM
P: 2,491
Quote Quote by mymachine View Post
Am I that really not so nice?

I just telling that was wrong.

No other purpose.
Okay, but its considered harsh to say it that way.

Instead most people would say: No, there's only one box.


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