ROFLQUESTION rates of change ROFLQUESTION (1 Viewer)

[menty]

Water is being pumped into a pool at 2metres cubed per minute. The pool is 20m long and 5m wide. Itts depth decreases uniformly from 5m to 1m at the other end.
A) show the volume of water at depth h is 12.5h^2. Hence find he rate of increase of i) depth and ii) SA of the water when the water depth at the deepest end is on metre

 

[justchillin]

Area trap = 1/2xhx5(h) at depth = h
therefore volume = 25/2h^2 (width = 5)
U can do the rest...just chain rule, use ur head lol

 

[menty]

ta lollerchillin. Just couldnt work out the roflarea.

what i dont get is why the area isnt H X 20

 

[justchillin]

Draw a diagram..id put mine up but im spastic with computers...gl tomorrow mate

 

[Stefano]

Area trap = 1/2xhx5(h) at depth = h

Could you explain that? are you using the fact that the Area of a RHS triangle is ab/2 ? If so where did you get 5h from ?

ta lollerchillin. Just couldnt work out the roflarea.

lmao, you sound like someone who plays too much Counter-Strike

 

[Stefano]

Justchillin: http://community.boredofstudies.org/showthread.php?p=1969023#post1969023

 

[justchillin]

K at x=h draw a horizontal line going 2 the deep end. Then use pythagoras on the top triangle to work out perpendicular heights...comes out at 5h for me...fuck i need 2 put my diagram up but i cant seriously...its like a trap face with depth = 5 on left and depth = 1 on right...

 

[menty]

ahaha. LOL LOL ROFLBURGER LOL LOL

ROFL ATTAACK CHOPPER

 

[Stefano]

K at x=h draw a horizontal line going 2 the deep end. Then use pythagoras on the top triangle to work out perpendicular heights...comes out at 5h for me...fuck i need 2 put my diagram up but i cant seriously...its like a trap face with depth = 5 on left and depth = 1 on right...

Don't fret about a diagram. I'm pretty sure mine is correct.

What's the length of the hypotenuse??

 

[Stefano]

ahaha. LOL LOL ROFLBURGER LOL LOL

ROFL ATTAACK CHOPPER

ROFLMAO!

OMFGBBQH4X!!!

 

[menty]

but seriosuly, i cant see it.
Does the h go horizontal or vertical (in between the 5 and 1)
i keep on getting 20h^2 as my volume

 

[justchillin]

sorry my internet has been down...I dont really know how 2 explain it apart from what I've been saying...what bit are u unsure about? And stefano what was that link: i dont get it?
Edit: you dont need the length of the hypotenuse... the 2 sides are h and 5 and the perpindicular height is found using right angled triangle...

 

[robbo_145]

diagram.....

 

[Stefano]

The link was a...link... lol.. to a thread of mine entitled 'Quick Polynomial Question' in the 3u forums. Check it out. No-one has been able to help yet. I thought maybe you could?