13 replies to this topic

[A Silent Soliloquy]

I have a test tmrw and my teacher never taught me this:

A ball is held at rest on a balcony 15 m above the ground. Then it is dropped and accelerates freely. With what velocity does it strike the ground?

It says the answer is 17m/s [down] but I dont get it

Please as soon as you can because its tomorrow >_>

This is all the information provided nothing more.

Edited by The Golden Cheesepuff, 22 May 2008 - 08:10 PM.

[Melchoire]

initial velocty = 0m/s
final velocity = x m/s
accelaration: -9.8m/s²
distance = -15 m

final velocity squared = initial velocity squared + 2(accelaration)(distance)
x^2 = 0^2 + 2(-9.8)(-15)
x=-17.1 m/s

Edit: it's important to choose a direction to be negative and another to be positive. In this case since acceleration is downwards it's -9.8 and since it's going down the distance is -15.

Edited by FlashGM, 22 May 2008 - 08:34 PM.

[Noitidart]

wow flash you really hit it hard, nice lil tut. did that help cheespuff?

[Melchoire]

wow flash you really hit it hard, nice lil tut. did that help cheespuff?

NOIT!!! when did you get back?!?!
How's it been man? I didn't even see that thread >_<

[Noitidart]

NOIT!!! when did you get back?!?!
How's it been man? I didn't even see that thread >_<

hehe hiiii broooo!!!
well just day before yesterday
and im trying to pop everyday now!

how ya been??

sorry cheesy me and gm gonna hi jack ur topic

[Melchoire]

hehe hiiii broooo!!!
well just day before yesterday
and im trying to pop everyday now!

how ya been??

sorry cheesy me and gm gonna hi jack ur topic

as long as you're active ! all the original admins seem to be disappearing

[Sweeney]

I'm sorry, but if you have a test, and you don't know the most basic equations of motion, you're fucked

[nox]

I'm sorry, but if you have a test, and you don't know the most basic equations of motion, you're fucked

especially at the end of the year...lol

[Noitidart]

i guess the prof just didnt teach it

all admins now in college

[A Silent Soliloquy]

initial velocty = 0m/s
final velocity = x m/s
accelaration: -9.8m/s²
distance = -15 m

final velocity squared = initial velocity squared + 2(accelaration)(distance)
x^2 = 0^2 + 2(-9.8)(-15)
x=-17.1 m/s

Edit: it's important to choose a direction to be negative and another to be positive. In this case since acceleration is downwards it's -9.8 and since it's going down the distance is -15.

Thanks youre my hero!

I'm sorry, but if you have a test, and you don't know the most basic equations of motion, you're fucked

Well we never did this specifically, all we did so far was like chemistry nomenclature and significant digits, etc.

especially at the end of the year...lol

I do physics chemistry and biology in one semester, its the same course 70minutes a day.

Well it ended up not being on the test and that chapter that had the question we didnt even cover

[Melchoire]

Well we never did this specifically, all we did so far was like chemistry nomenclature and significant digits, etc.

If you ever get the chance please punch your teacher square in the jaw for teaching sig. figs. 7 is the same fucking number as 7.00 >_<

[A Silent Soliloquy]

If you ever get the chance please punch your teacher square in the jaw for teaching sig. figs. 7 is the same fucking number as 7.00 >_<

The worst part is:

7 x 10^3 is not equal to
7.0 x 10^3 is not equal to
7.00 x 10^3

if you consider significant digits >_>

[Melchoire]

The worst part is:

7 x 10^3 is not equal to
7.0 x 10^3 is not equal to
7.00 x 10^3

if you consider significant digits >_>

It's just another way to needlessly make school even more pointless.

[tastyphoxette]

I assume the test has already happened...

So how'd it go? Do you think you got it?