00:01
So in this problem, we have a golf ball, and it is hit into the air from the initial position, has some position one, and a final position of two.
00:13
The correct answers for part nine talking about velocities and acceleration are given.
00:18
Let's talk about the concept real quick.
00:20
The acceleration through this entire flight path is constant.
00:26
There is the acceleration due to gravity g that happens the same at every path.
00:35
And that's only in the y direction, not in the x direction, because in the x direction, if we ignore air resistance, it's a constant x speed through the entire path, but the y changes some.
00:50
So that part c was talking about accelerations, and then for part d, we have velocities.
00:58
So as i talked about before, the x, the x velocity is the same, but the velocity and the y changes.
01:06
Some, it starts, vy starts at some positive value because the ball is going up, but then as it reaches the top, it gets smaller, and then starts going down.
01:19
So the total velocity is the same as the resultant of both the components, which means because one component is getting smaller at the top, the velocity is lowest right here where vy is equal to zero.
01:34
And then as the vy component it goes non -zero, then the total velocity starts getting bigger.
01:45
The answer for part g is the same discussion about vys, where it starts at some positive value, and then because we have velocity and acceleration in different directions, the velocity goes and gets smaller over time until it reaches here.
02:05
And so that was relating that.
02:08
As well as part h is talking about that the x velocity is constant.
02:12
Because there's no acceleration in the extraction, and so we know from newton's first law that object in motion tends to stay in motion, and so the vx stays constant...