00:01
For this problem, we have a skydiver jumping from a plane, and we see that this skydiver is moving downward and slowing down at a rate of 2 .4 meters per second squared.
00:14
So that means that their velocity is positive down, and their acceleration then would be negative because it's going in the opposite direction of motion.
00:26
And that acceleration then is equal to negative 2 .4 meters per second squared.
00:35
We also can go back and draw a free body diagram for the skydiver with a parachute out.
00:42
The line that we have that is straight down will be the mass times gravity or the force due to gravity, and straight up will be the tension in the lines of that parachute.
00:55
We also need to now do a sum of the forces in the y direction, and we know because it's accelerating that this is equal to mass times acceleration.
01:09
Let's go ahead and define down as positive, since we've already done that over here.
01:15
And now that we've defined what's positive, we're going to take that positive piece, which is mg.
01:21
We're going to subtract what's going in the opposite direction, which is tension, and that's equal to the mass times the acceleration...
