00:01
In this problem, we're considering a smooth ball.
00:03
The smooth ball is a diameter of 40 millimeters and the mass to 50 grams, and it's thrown upward with a vertical speed of 30 meters per second.
00:14
The temperature is 20 degrees.
00:20
And what else do we know here? this is equal to 0 .050 kilograms.
00:32
This is 0 .0 450.
00:35
Our density of our air will be at 20 degrees as 1 .5 .0 .4 .0 .0 .0 .0 .0.
00:40
Our density of our air will be at 20 degrees as 1 .202.
00:47
And our kinematic viscosity is 15 .1, there's an 18 .15 .1 times 10 to the minus 6 meters squared per second.
01:04
Energy is 9 .81 meters per second squared.
01:12
Okay.
01:13
And let's do a free body diagram.
01:14
So here i have w, here i have fd.
01:23
Here we have this.
01:26
And we know that the sum of my forces of y equals m -a, f -d plus w equals m -a.
01:38
And here's my w, there's my f -d.
01:43
Okay, and let's solve for a.
01:51
And that will be f -d plus w, divided by so now we also know, let's consider a drag weight here.
02:04
Our drag will be equal to one half.
02:17
So we need the area, which will be equal to pi times d over two squared.
02:29
And our reynolds number will be, okay, and then we can plug it some values to get this.
02:43
Okay.
03:03
Where's my calculator? let me get that.
03:07
Got it? opening.
03:10
Please be charged.
03:11
Please be charged.
03:12
Ah, yes.
03:14
So i've got 0 .05 times 9 .81.
03:19
This gives me 0 .4905 newtons.
03:29
Then let's find the area of our sphere.
03:36
0 .040 over 2 squared will equal 2 2 .5 times.
03:54
Parentheses and here i get 0 .001 ,256, 6 meters squared.
04:12
And then my red will be u, oops, and this will equal 20.
04:26
Was it 20? 30, my bad.
04:37
30 meters per second times 0 .0.
04:54
40 divided by 15 .1 times 10 to the minus 6 meter squared per second.
05:05
And this will equal 56, 954.
05:13
And my red will therefore be equal to 5 .7 times 10 to the fourth.
05:23
Okay.
05:24
And then let's do some.
05:29
And the figure that gives us, we're going to find a figure.
05:40
We know that, r -e -d and that will be 5 .7 times 10 to the fourth.
05:51
What just happened here? i'm just quit.
06:01
That was unusual.
06:09
I just had something very unusual happen.
06:39
Hang on...