Problems 42, 43, 44, 45, 46, 47, 48, 49, 50, 51, and 52 describe a situation. For each, draw a motion diagram, a force-identification diagram, and a free-body diagram. A model rocket is fired straight down from the top of a tower.

Video transcript

Hey, everyone in this problem, we're asked to provide three things. The first being a motion diagram, the second being a force identification diagram. And the third being a free body diagram for a spaceship from outer space accelerating vertically downward in the earth's atmosphere. So we're gonna start with part one. We want a motion diagram. OK. So we want a motion diagram. We're gonna show how the speed is changing for this spaceship. OK. So we're told is that this spaceship is accelerating vertically downward. So our acceleration is gonna be going downwards if we're accelerating downwards, that means our speed is getting larger, their velocity is getting larger as we go down. OK? If we're getting a larger speed, that means we're gonna be covering more distance in the same amount of time. So when we draw a motion diagram, we're gonna have our points. OK? And then we're gonna have our arrows between those points and in this case, the arrows between the points are gonna be getting larger. Hey, those points each represent a particular time interval. OK? So the time interval between each point is the same, we're covering more distance in the same amount of time because our speed is increasing, we have acceleration. So this is our motion diagram showing that speed, our acceleration is increasing and that's everything we need for the part. First part. So we're done with the first part, we can move on to part two and part two is looking at a force identification diagram. Now, for the force identification diagram, we wanna go ahead and draw out the object we have so we can draw out our spaceship. OK. That's our spaceship. And we want to identify all of the forces acting on this spaceship. All we can do is start with the net force. We know that this spaceship is accelerating downwards. So by Newton's second law, the force and the acceleration act in the same direction, so the net force is going to also be acting down. And when we think about this spaceship moving um in earth's atmosphere and because it's in earth's atmosphere, there's gonna be a force of gravity. So that force of gravity is gonna act towards the earth, we know that there's gonna be some sort of thrust force due to the rocket engines. And we also know that there's going to be a drag, you know, the thrust force is going to propel it in the direction of the net force, we'll call that ft and the drag force is going to oppose the motion. It's like a frictional force when we have something moving in air. So it's gonna oppose the motion. This spaceship is moving downwards. So the drag force is gonna be pointing upwards and those are all of the forces we have acting on that spaceship. So that is our force identification diagram. So part two is done and we can move now to part three and part three is a free body diagram. So in a free body diagram, we're identifying those forces again, we're just being a little more specific and precise with that. So we're gonna draw our spaceship as a point. OK. And we're gonna label all of our forces. So we have the force of gravity acting downwards, the thrust force acting downwards, the drag force acting upwards and our net force will act dumb if we're just building upon what we did in our fourth identification diagram and drawing it in that format of a free body diagram. And that's it for this question. Those are all three diagrams that we were asked to draw. I hope this video helped see you in the next one.