Help I can't figure negative acceleration
- Thread starter staceyrho
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skeeter
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from 632 mph to rest in 1.4 seconds? that's one **** of an acceleration ...
all you can figure out from this given info is average acceleration,
\(\displaystyle \L a = \frac{\Delta v}{\Delta t}\)
you first have to convert 632 miles/hr into ft/s, then use the above equation to calculate acceleration in ft/s<sup>2</sup>.
you should get a = -662 ft/s<sup>2</sup>.
all you can figure out from this given info is average acceleration,
\(\displaystyle \L a = \frac{\Delta v}{\Delta t}\)
you first have to convert 632 miles/hr into ft/s, then use the above equation to calculate acceleration in ft/s<sup>2</sup>.
you should get a = -662 ft/s<sup>2</sup>.
I figured that this was how to do it, but nothing in my Physics book states how to figure negitave acceleration, so I thought maybe I needed to be doing something else. If this helps here is the exact question:
A man rode a rocket-propelled sled that moved down the track at 632 mi/h. He and the sled were safely brought to rest in 1.4s.
Determine the negative acceleration he experienced. Answer in units of ft?x^2.
A man rode a rocket-propelled sled that moved down the track at 632 mi/h. He and the sled were safely brought to rest in 1.4s.
Determine the negative acceleration he experienced. Answer in units of ft?x^2.
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Since negative acceleration is just a negatively-signed acceleration, I'm not sure why this would (should?) be quanlitatively different from positive acceleration...? That would be like saying the "formulas" for negative velocities (driving in reverse) should, for some reason, be entirely different from the "formulas" for positive velocities (driving forward). Why would they differ, other than in sign?staceyrho said:
Note: One of the things you should be learning at this stage in your studies is how to see the logic of a topic and create your own situation-specific formulas. There is, after all, no way to provide a formula for every possible situation.
Eliz.
Okay on part two of this question I need to find the distance he traveled during his negative acceleration? I used this formula and it didn't come out correctly. Here's what i did can anyone tell me what i'm doing wrong.
V=V+at=
V= v/2
x= vt
Is this the correct way to figure this or am I doing too much too little.
V=V+at=
V= v/2
x= vt
Is this the correct way to figure this or am I doing too much too little.
Okay I used this formula, tell me if this is correct
x=1/2 (vo+vf)t
x=1/2 (15.45 ft/s^2)1.4s= 10.815ft
I got 10.815 ft for my answer. But my homework site it saying that's wrong. My velocity here is 632 mi/h which converts to 15.45 ft/s correct? I don't think I need to figure in my netagive acceleration from the first part of the problem.
x=1/2 (vo+vf)t
x=1/2 (15.45 ft/s^2)1.4s= 10.815ft
I got 10.815 ft for my answer. But my homework site it saying that's wrong. My velocity here is 632 mi/h which converts to 15.45 ft/s correct? I don't think I need to figure in my netagive acceleration from the first part of the problem.
I'm not sure I understand what you mean. This physics stuff is all new to me and i'm just trying to learn from people who know more than I do. One thing I've found on this site is that I get responces in terms that I have to question over and over again. You all need to realize that those of us asking the questions here are not at your math level. You need to speak in terms we would understand, or we wouldn't be asking. That's like taking something your not good at and asking someone and their explaining it in terms you don't undertand what so ever. Math happens to be one of my weak spots and I'm trying to get all the help I can. This website for the most part has helped me out. But When I don't understand something it would be nice to just be shown in terms I understand.
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It should be noted that nobody has demanded that you "get up where the experts are". But it has been requested that you kindly format, punctuate, etc, clearly, so that the tutors can decipher what you mean. (It is difficult to provide answers when the question is unintellible.)
Also, there is a certain amount of "terminology", etc, with which you should, as a student at this level, be familiar: If you are taking physics, then you should be familiar with the physics terms they are using in class. The tutors are "tutors" (rather than "experts in the field, who you happened to run into in the produce department") in part specifically because they are using the "simple" terms.
In this case, the tutors have thus far asked you please to show your work, to post the actual exercise, to be careful with your units, to check your arithmetic, and to write neatly. Which part of this has been so confusing and mean?
If you are in a physics class (or related math class), but aren't familiar with the meaning of the word "organized" (the only "big word" in the post to which you appear to have objected), then I'm afraid that the assistance you need is well beyond anything we can provide here. Sorry.
Eliz.
Also, there is a certain amount of "terminology", etc, with which you should, as a student at this level, be familiar: If you are taking physics, then you should be familiar with the physics terms they are using in class. The tutors are "tutors" (rather than "experts in the field, who you happened to run into in the produce department") in part specifically because they are using the "simple" terms.
In this case, the tutors have thus far asked you please to show your work, to post the actual exercise, to be careful with your units, to check your arithmetic, and to write neatly. Which part of this has been so confusing and mean?
If you are in a physics class (or related math class), but aren't familiar with the meaning of the word "organized" (the only "big word" in the post to which you appear to have objected), then I'm afraid that the assistance you need is well beyond anything we can provide here. Sorry.
Eliz.