Work and Fluid Force: Calculus II

[think4432]

The only thing you had wrong in your original post was the depth of 5-y instead of -y. Why are you now suddenly saying y goes from 0 to 4? Don't you remember your choice of coordinates?

Oh! Oh! Oh!

Sorry! Sorry! I was looking at the other thread and got mixed up!

The limits are -5 to -1!

-154/3?

I did something wrong?

 

[LCKurtz]

Oh! Oh! Oh!

Sorry! Sorry! I was looking at the other thread and got mixed up!

The limits are -5 to -1!

-154/3?

I did something wrong?

Do you have -5 as the lower limit and -1 as the upper like you should? It should come out positive and don't forget the water density.

 

[think4432]

Do you have -5 as the lower limit and -1 as the upper like you should? It should come out positive and don't forget the water density.

Theres no pi in this problem, correct?

So the problem is just the limits a = -1 and b = -5 and integrating (7/24)(y^2) + (2y+3)

With the water density of 62.4 lb/ft^3 outside of the integral as a constant? Correct?

 

[think4432]

I still get 154/3(62.4)

And then when I multiply that out I get 3203.2 ft(lb)

 

[LCKurtz]

Do you have -5 as the lower limit and -1 as the upper like you should? It should come out positive and don't forget the water density.

Theres no pi in this problem, correct?

So the problem is just the limits a = -1 and b = -5...

Did you read my question: Do you have -5 as the lower limit and -1 as the upper like you should?

 

[think4432]

Did you read my question: Do you have -5 as the lower limit and -1 as the upper like you should?

Yes. Sorry I just had a typo A = -5 and B = -1

When you evaluate -5 [lower limit] you get -1225/24
And when you evaluate the -1 [upper limit] you get 7/24

So 7/24 - (-1225/24)

You get 154/3 times the weight density.

Which is 154/3 * 62.4

= 3203.2

?

 

[LCKurtz]

I still get 154/3(62.4)

And then when I multiply that out I get 3203.2 ft(lb)

The numbers look OK now. But you need to quit guessing at the units. What was this problem asking for? What would the correct units for the answer be? Do you actually get those units?

I'm going offline now for the rest of the day. People arriving for big Father's Day party. Hopefully you can finish it up.

 

[think4432]

The numbers look OK now. But you need to quit guessing at the units. What was this problem asking for? What would the correct units for the answer be? Do you actually get those units?

I'm going offline now for the rest of the day. People arriving for big Father's Day party. Hopefully you can finish it up.

Ok! Thank you very much.

Happy Fathers Day to you! Hope you enjoy the rest of your day!

Thanks so much for your help though.

You are great.