00:02
So, we know that force is equal to pressure into area.
00:08
So, pressure is rho g into d where rho is mass density, g is acceleration due to gravity and d is depth.
00:19
So, this is a non -metric problem.
00:21
So, we can write delta equals to rho into g.
00:27
So, where this is what weight density of water.
00:31
So, this is equal to 62 .5 lb upon feet cube, pounds per feet cube.
00:40
Now, hydrostatic force is what? rho g d into a.
00:47
So, rho g will be replaced by sigma d into a.
00:52
Now, we are taking, so that's a surface of the water is at x equal to 0 and we will consider downward depth as positive.
01:00
So, depth will become, we are starting from x equals to 0.
01:10
So, depth of the plate is from x equal to 2 to x equal to 2 plus 5 that is x equal to 7.
01:17
So, if we look at the graph, so this point is 2 comma 0 and this is 7 comma 10.
01:30
So, if you try to find the equation of line, this will be y equals to 2x minus 4.
01:40
Now, if we divide the interval, this is 7 comma 0.
01:47
So, we divide the interval between 2 to 7 into subintervals of equivalent with endpoints xi and let's call xi star.
01:59
So, this represents any particular xi.
02:06
Now, we can write the area of a thin horizontal strip of height del x on the triangular plate...