ATAR Notes: Forum

VCE Stuff => VCE Mathematics => VCE Mathematics/Science/Technology => VCE Subjects + Help => VCE Specialist Mathematics => Topic started by: Zebra on November 09, 2011, 09:47:24 pm

Title: last minute question
Post by: Zebra on November 09, 2011, 09:47:24 pm
2007 question 5.

WHY DO YOU USE CONSTANT ACC FORMULA?????????????????????????????????????????????????//

WHERE DOES IT TELL YOU THE ACC IS CONSTANT??????????????????????????????????????????????????


why can't you just use initial v, final v, time to work out acc?
Title: Re: last minute question
Post by: Zebra on November 09, 2011, 10:05:05 pm
my fucking goodness....

no sleep tonight!
Title: Re: last minute question
Post by: dc302 on November 09, 2011, 10:10:12 pm
Are you talking about exam 1? The acceleration is definitely constant, because there are no forces acting on it except friction (and friction is a constant force here).


edit: and yes you can, and you ARE using the initial/final v and time.

edit2: what I meant by my first edit is:

the constant accel formula is this:   v=u+at. That is precisely using the initial and final velocities and time taken ie, a = (v-u)/t
Title: Re: last minute question
Post by: jane1234 on November 09, 2011, 10:22:47 pm
Ha just did this exam. :)

Constant forces = constant acceleration.

You are not given t so you have to use v^2 = u^2 + 2as where s = 3, u = 4 and v = 0.
Title: Re: last minute question
Post by: dc302 on November 09, 2011, 10:25:48 pm
Ha just did this exam. :)

Constant forces = constant acceleration.

You are not given t so you have to use v^2 = u^2 + 2as where s = 3, u = 4 and v = 0.

Oops, my mistake. Read 3 seconds instead of 3m hah :D
Title: Re: last minute question
Post by: Zebra on November 09, 2011, 10:49:22 pm
Ha just did this exam. :)

Constant forces = constant acceleration.

You are not given t so you have to use v^2 = u^2 + 2as where s = 3, u = 4 and v = 0.

Oops, my mistake. Read 3 seconds instead of 3m hah :D
same.

okay. i thought this shit was new guys. thanks! and good luck...

if you guys are not asleep, 2006 question 4)a) (exam 1) ?

i used lami's and got it wrong!
Title: Re: last minute question
Post by: Zebra on November 09, 2011, 10:55:07 pm
got it. thanks to itute... !
Title: Re: last minute question
Post by: Andiio on November 09, 2011, 10:58:14 pm
When you prove a rectangle, do you have to prove ALL angles are right angles?
Title: Re: last minute question
Post by: AleksIlia on November 09, 2011, 11:00:33 pm
When you prove a rectangle, do you have to prove ALL angles are right angles?

No just one pair of sides afaik.
Title: Re: last minute question
Post by: ellecee on November 09, 2011, 11:01:16 pm
You can also prove that the diagonals are of equal length
Title: Re: last minute question
Post by: Andiio on November 09, 2011, 11:02:01 pm
So say for ABCD, would you be able to attain full marks if you just proved angle(ABC) and angle(BAC) are right angles?
Title: Re: last minute question
Post by: Andiio on November 09, 2011, 11:03:53 pm
You can also prove that the diagonals are of equal length

How would you differentiate a square from a rectangle then, if you just prove that the diagonals are equal in magnitude? (I'm thinking that this is a stupid Q which I know the answer to :P)
Title: Re: last minute question
Post by: davidle_10 on November 09, 2011, 11:13:20 pm
You can also prove that the diagonals are of equal length

How would you differentiate a square from a rectangle then, if you just prove that the diagonals are equal in magnitude? (I'm thinking that this is a stupid Q which I know the answer to :P)
Lol, to differentiate a square from a rectangle the magnitude of all lengths of the square are the same.
Title: Re: last minute question
Post by: ellecee on November 09, 2011, 11:13:34 pm
You can also prove that the diagonals are of equal length

How would you differentiate a square from a rectangle then, if you just prove that the diagonals are equal in magnitude? (I'm thinking that this is a stupid Q which I know the answer to :P)

You don't. Squares are merely a special rectangle. :)
Title: Re: last minute question
Post by: Zebra on November 09, 2011, 11:29:42 pm
if asked to prove something is a kite how would you guys do it?
Title: Re: last minute question
Post by: kenny_ on November 09, 2011, 11:51:53 pm
On one of the assessment reports, VCAA states that a square is a type of rectangle
Title: Re: last minute question
Post by: Zebra on November 10, 2011, 12:09:22 am
FUCK
Title: Re: last minute question
Post by: Mao on November 10, 2011, 01:25:20 am
if asked to prove something is a kite how would you guys do it?

Let a kite be ABCD, with the longer axis AC and shorter axis BD.

Then you must show that:
|AB|=|AD|
|CB|=|CD|
|AB|=/=|CB|

and that would be sufficient.
Title: Re: last minute question
Post by: Zebra on November 10, 2011, 10:50:30 am
good lord. this didn't come up.
learn it for tmrw!