00:01
Hi there, so for this problem, we're told that the flow of blood in a blood vessel is given by the expression that we're given in here.
00:17
And that will be that capital b is equal to p divided by 4 times l times the speed.
00:25
This times the radius r square is the radius of the blood vessel.
00:30
And this minus lower case r to the square, where that is the distance of the blood vessel from the center of the vessel.
00:40
And p and l and b are physical constants related to the pressure, length, and viscosity of the blood vessels.
00:52
So with that said, first of all, we need to assume that the rate of change of the speed with respect to time is measuring millimeters per second, a square, we need to assume that the radius is a constant as well as b, l, and b.
01:10
So for part a of this problem, we are asked to find the rate of change of this expression with respect to time.
01:19
And this, in terms of the radios and the rate of change of the radius would respect to time.
01:27
And we are given numerical values for l, which is 70 ,000.
01:32
Limiters, p is 400, and b is just 0 .003, which is the viscosity.
01:47
So with that said, let's just solve this problem.
01:50
So if we take the expression that we are given and take its derivative with respect to time, that will be 2 times p times the radius, this divided by 4 times the length.
02:06
Times b, and this times the rate of change of the radius with respect to time.
02:12
We know that the its derivative of this is just zero because it is a constant, okay? now we just need to simply substituting here the values, so that will be 2 times the pressure that is 400, and this divided by 4 times the length that is 70 times 10 to the minus 3.
02:33
This times 0 .003.
02:39
This times the radius times the rate of change of the radius with respect to time.
02:44
So let me simplify that in here.
02:47
So we'll have 4 times 70 times the 10 to the minus 3.
02:53
This times 0 .003.
02:56
We take the inverse of that and we multiply that by 2 times 400.
03:02
So, well, let me just, okay, let me just verify that.
03:15
So that will give us a value of 9 .5 ,000, sorry, 524 times 10 to the 3...