Physics is just what is this.

[Mateo]

I've been having trouble on this problem in physics since monday. I've been given no other problems like it, I have found no formulas I could use to solve it, and to me it just seems all around impossible. I'm sure if someone better at this kind of thing than I am would point out the error of my ways I'd see I'm wrong, but for now this is just ridiculous.

003 (part 1 of 3) 2.0 points
A hockey puck sliding on a frozen lake comes
to rest after traveling 190 m.
If its initial velocity is 1.6 m/s, what is its
acceleration if that acceleration is assumed
constant? Answer in units of m/s2.
004 (part 2 of 3) 2.0 points
How long is it in motion? Answer in units of
s.
005 (part 3 of 3) 2.0 points
What is its speed after traveling 145 m? An-
swer in units of m/s.

The bold is what I need to know now.

The acceleration is already known: -0.0067368421 (Sadly, I've memorized this number.)


There are only 2 ways I can see to set up this problem.

Code: [Select]

Solving for Vf

Vi=1.6m/s
d=145
a= -0.0067368421

or

Code: [Select]

Solving for Vi

Vf=0
d=45
a= -0.0067368421
The assignment is due at 10:00 tonight through the intrenets, so ye... Kind of in a hurry.

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[tay104]

You should probably have asked your teacher for help.  Also, did you check for the formula in your textbook?

[Mateo]

Well every formula I have, every formula every person I've asked has had, and every formula I could find in my book really didn't help me with this. I mean the one I did find where the things I had fit it turned out to be some ridiculous answer. If you ask me I probably forgeted up the setup.

Also the main reason I hate these damn online assignments is because my printers a bitch which makes it really difficult to ask the teacher for help. :/

[FlyGuy45]

Doing, one sec.

I think your acceleration should say -.0067....

using DeltaX=Vt=90.63

[Mateo]

Doing, one sec.

I think your acceleration should say -.0067....

using DeltaX=Vt=90.63

D:< forget I wrote down and memorized the wrong acceleration. you are correct my good sir. I can probably solve it now.

Oops. Nope no I can't. Man I loving fail. I guess it doesn't really matter I'll just get it wrong and keep this 1 assignment at a C- instead of an A-.

[FlyGuy45]

I tried solving this way:

Solve for time of 190=237.5

145/190=.763

.763(237.5)=181.21

145/181.21=.8 m/s^2

My teacher does it online too, I hate it.

We get 4 attempts per assignments.

[Mateo]

I tried solving this way:

Solve for time of 190=237.5

145/190=.763

.763(237.5)=181.21

145/181.21=.8 m/s^2

My teacher does it online too, I hate it.

Well, Im trying to figure out the answer to the last question... I have the first 2 done already. I'm really just confused as hell as to what anything has to do with anything when it comes to this problem right now. I've tried so much random stuff it's just... bleh.

[FlyGuy45]

Well, Im trying to figure out the answer to the last question... I have the first 2 done already. I'm really just confused as hell as to what anything has to do with anything when it comes to this problem right now. I've tried so much random stuff it's just... bleh.

This is the last question.

[Mateo]

This is the last question.

Why did you give me acceleration then?

Or was that a mistake in units.

EDIT: Also just by the by, it says .8 is incorrect. :<

[FlyGuy45]

Why did you give me acceleration then?

Or was that a mistake in units.

Mistake in units.

[Mateo]

Well. This is just absolutely ridiculous. I'll just ask my teacher where I went wrong... ;_;

[FlyGuy45]

145=1.6t+1/2(.0067)t^2 should work, but I am getting ridiculous numbers.

[Mateo]

if the same variable is in 2 different forms (for instance, when t isn't squared and when it is) you can't solve for it unless 0 cancels out one of the variables. I don't know how you were getting numbers with that equation. ._.

take this equation as a simplified example: x + x^2 = 2

[FlyGuy45]

Quadratic formula .

[Saxophone]

Is this what college stuff is like?