http://m.youtube.com/watch?v=wiZoVAZGgsw
Run the numbers!
Do they agree?
If not why?
What is the force the track exerts on the car at the top of the loop?
What if the top of the track were missing? How would effect the result?
Does the observation below match your prediction?
Any loop problem is interesting because both the normal force and the gravitational force point towards the center of the circle created by the loop itself. Since the the orientation of the car on the track is continuously changing, the normal force is continuously changing its direction as well. This gives off the feeling of weightlessness because there isn't a force that is exerted from the track at the top.
ReplyDeleteRelating to this situation is the possibility of not having the top of the loop. Because there isn't a force exerted from the track at the top, I predicted that it wouldn't really effect the result it everything was done correctly. (correct speed, etc)
- Rachel R
That video was actually really cool. My numbers did agree when I ran them. In this problem, the car experienced many forces. The horizontal force was the force of friction. The vertical forces were the force of gravity and the normal force. What was interesting about these forces was that gravity was always pointing down, but the normal force was always pointing towards the center. This caused it to constantly be changing while the car was in motion. Interestingly, when the car was at the top of the loop both forces pointed in the same direction. This meant that the track was exerting no force on the car, causing the driver to feel weightless. For this reason, if the top of the track was missing, the car would travel along the same path. This piece of the track has very little impact on the car's motion. My prediction matched the observation in the video.
ReplyDeleteI agree that this video was really cool! There are three forces that I can identify acting on the car: gravity, friction, and normal force. Gravity is a constant, always pointing down, but in this particular video the normal force always pointed towards the center (like in the lab "Hooked on Physics"). Both the gravitational force and normal force act downwards at the top of the loop. The force of friction always acts between two parallel surfaces. If the top of the track was missing, the car would continue traveling on the path it was taking until gravity eventually pulled it back down to the earth.
ReplyDeleteI also agree that the video was very cool. After running my numbers I do agree with the video. In my calculations I found the forces of both normal force and gravitational force to be acting on the car. In any loop problem Gravity is always pointing down and constant in acceleration (-9.8), but this case allows normal force to always point toward the center. At the top of the loop both normal force and gravitational force act down causing not force to be exerted by the tracks. For this reason I concluded that if the top of the track was missing the impact on the car would be slim to non. My prediction did also match the observation in the video.
ReplyDelete-Emily F
Cool vid bro. My numbers did agree with the video and the observations I made from watching it. The only forces acting on the car while going through the loop were gravity, normal force, and gravity, and of course the resulted centripetal force. Gravity is always pointing towards the center of the earth, normal force is always pointing perpendicular to the track, and friction is parallel to the surface. What is interesting about the very top of the loop is that gravity and normal force are both pointing in the same direction, and so this is why someone in the car at that moment would feel weightless because they are technically only being pulled down. Also, this is the reason why if the track was removed at that point, the car would still continue in its same path because the track has no effect on it during that point. My prediction for the second video was correct as well.
ReplyDeleteI really enjoyed this video because it was interesting to see a force problem put into a real life scenario. You can write down numbers and calculate forces all day long, but actually applying it and being successful is what is truly amazing. Any case that has to do with a loop creates a very interesting circumstance (as many have said before me). At the bottom, gravity and normal force act opposite each other to keep the car on the track. However, at the top gravity and normal force are both working downwards. Whenever I take a loop problem and break it into separate parts, this is the piece that always confuses me. I can't help but want to say that the object should fall downward at the top. When looking at the entire picture though and factoring in speed and the changing normal force, it becomes clear that an object at the top of a loop will continue it's path. I had never considered the idea of removing the top of the track, but when watching the second video the continual motion makes sense.
ReplyDeleteThe force of gravity is constantly pointing downward, regardless of the position of the car because it is a constant. Normal force would alter depending on the position of the car, unlike the former. The normal force is parallel to the surface and is always pointing toward the center. The diagram of the motion is like most we have constructed in class. The equilibrium or the balance of the normal force and the force of gravity occurs at the base or the south point of the motion, the right (or east part of the motion) and left (or west part of the motion) would both have a normal force pointing toward the center and gravity downwards which would create an L-like shape (with different orientations), and the top of the motion would have the normal force and the force of gravity pointing in the same direction, essentially making the object or person feeling weightless because there is a lack of contrast to the downward pull toward the center. If the top were missing, I don't think it would have much of an effect. If it were not there, wouldn't the car continue in that motion? It would not suddenly break off and go tangent to the circle instead of completing the motion. My prediction did match the video.
ReplyDeleteThe numbers I "ran" through my calculator were sort of similar to the video so I would assume that it's that video was spot on, as I usually am not. At the top of the loop there were about three forces acting on the car, the normal force acting down towards the center of the loop, the gravitational force acting down towards the center of the Earth and the force of friction which allowed that car to stay on the loop at such a low speed, it acted in the opposite direction of the car's route. Technically speaking there would also be the centripetal force which is being caused by all the other forces and it acts towards the center of the loop, just like that normal force, so in this problem Fc=Fn. If the top of the track was missing the car would have to speed up a bit more to make up for the lack of friction, making it stay to the loop better.
ReplyDeleteI agree that the video was really cool and that the numbers would work. Overall the forces are gravity acting down, normal force always pointing to the center of the loop (perpendicular to the road), and friction acting opposite the way of the car. As well as these there would be a centripetal force being the sum of the others acting towards the center of the loop. At the top of the loop both normal force and gravity are going down. This makes the person feel weightless at the top. If the track was removed at the top, the car would continue in the loop because the forces at the top act down either way, and the track has little effect. My prediction matched the video.
ReplyDeleteI thought that video was pretty cool as well. After watching it, I figured the number stated in the video would work and it proved to work when the car went around and did not fly off. At the top of the roof, the track exerts a normal force downward and gravity does as well. There is also a component of friction that is acting in the opposite direction the car is travelling. I also agree with the other comments that the car would continue in the loop because the forces are both acting downward so taking away one of them does not change much. Yes, my predictions matched the video
ReplyDeleteEmma H
The numbers that were used in the first video were accurate, which is why the car stayed on the track the entire time and made it through the loop successfully. At the top of the loop, there are several forces that are exerted on the car. Gravity is exerted on the car in the downward direction throughout the loop. Also, normal force is exerted perpendicular to the track, which is straight down at the top of the loop. Lastly, friction is exerted in the direction opposite to the motion of the car. The result of these forces is the centripetal force. If the top of the loop were missing, the situation would not be substantially affected. At the top a majority of the normal force points in the same direction as gravity, so if the top was removed, gravity would still force the car downward. In the second video, my observation was proven. The person still reached the same height as when the loop was complete. However, some of the track that was removed pointed at an angle, so therefore, the person did not go as far sideways because there was no normal force pushing in the x-direction.
ReplyDeleteThis video was cool! The number also worked, beige the car stayed on the track. The car experiences several forces throughout it's journey, including friction (opposite of the car's direction), normal, (towards the center go the loop), and gravity (always down). The track exerts no force at the top of the loop, being normal force and gravity are down. if the track was missing the car would continue on a path going in the same direction and tangent to the point with no track. My predictions matched the video. -Kelly Glenn
ReplyDeleteThe video was really cool. The numbers I ran agreed with the numbers in the video. While going through the loop, there were always three forces acting on the car. The three forces were gravity, normal force, and the force of friction. Also the centripetal force was present as a result of other forces acting upon one another and of course because of the circular motion. Gravity was pointing down at any given point in the loop as it always is pointing down, but what was interesting was the normal force which was always pointing towards the center. Also, friction was always in the opposite direction of the motion of the car. Because at the top of the loop both the normal force and gravity were pointing downwards, no forces were being exerted on the car at that point which in result caused a feeling of weightlessness. If the top of the track were missing the car would still continue on the same path because it would continue on in a path tangent to where it left the track. My predictions also matched the video.
ReplyDeletethe calculations done if the first video were accurate, which is obviously why the car safely made it around the track. gravity, friction, and normal force are all apparent in this situation. gravity is always facing downward in the loop, normal force is always perpendicular to the track, or towards the center of the loop, and friction was always opposing the direction of the car's motion. at the top of the loop gravity and mormal force are facing the same direction, meaning no forces were being exerted on the car, giving the driver a feeling of weightlessness. the top of the tract could be removed and nothng would really change. this is shown in the second video.
ReplyDeletewhat would happen if the car drove on the outside of the track?
ReplyDelete