00:01
Find the fluid force on this triangular shape and the formula for fluid force is a to b which is bottom to top weight of the water dip the depth of the little strip here the length of this strip d y.
00:16
Okay so w 62 .4 strip depth from here down to there that will be negative y length of strip this side minus this side or it's symmetric so it's going to be 2x.
00:36
So length to x.
00:40
Oh, we can't use that because we're integrating with respect to y, so we're going to find out how x and y are related.
00:46
Well, they're on this line here, has slope 1, goes through minus 5, so y equals negative x, sorry, y equals positive x, minus 5, or x equals y plus 5.
01:03
So the length to y plus 10.
01:08
All right, so the force negative forces in a row negative 5 to negative 2, 62 .4 times negative y times 2y plus 10, dy.
01:31
So minus 62 .4, negative 5 to negative 2, 2y squared plus 10, d .y.
01:46
So negative 62 .4, 2y cubed over 3 plus 5 y squared from negative 5 to negative 2...