2006 VCAA exam - Motion Section (first section)

[MissIraq]

http://www.vcaa.vic.edu.au/vce/studies/physics/pastexams/2006/physics1w06.pdf

^ Are all thoes questions in the motion section possible to be found on the exam this year? Because I found they very hard.

Also what exam or exam companies are the closest to the vcaa type, so I can do them.

Also, Does anyone have new exams I mean for only our study design of 2009->

Thank you

[MissIraq]

Also, I have a question;

A fat 2kg cat falls of a tree. It falls 5m but is able to land on its feet and it takes 0.05seconds to come to a stop. It then scampers back up the tree.

Question; What is the average force the cat needs to exert against the ground to stop its falls in 0.05 seconds?

I tryed; F=ma , 2 x 10 = 20N ... Then Impulse = Ft, Impluse = 20 x 0.05

=1Ns ... But its incorrect, why is this method incorrect?

[xZero]

because F=ma is the net force, not the actual force the cat will be experiencing when it lands on the ground, use P=MV and change in p = I instead and solve for F.

[luffy]

My method seems long-winded, and might be incorrect, but this would be my solution:

To find average net force, you need to know the impulse. In order to find impulse (change in momentum), you need to know the velocity of the cat, right when it hits the ground. Thus, use the rules for motion

Vertically:
u = 0
v = ?
a = 10
x = 5









Now, find the momentum:







Obviously, as it has landed on the ground, the momentum will be 0.

Thus, the impulse = 20 Ns

F_average =





Hope I'm right xD.

[xZero]

yup, nice work  (still not used to seeing g=-10ms^-2 in physics)

[MissIraq]

Thanks guys

Also this question, I think theirs a mistake buy i dont really know.

Ghabi and Athwal are walking in the park listening to music, and not taking much notice where they are going. Ghabi is walking south at 5m/s and Athwal is walking west, also at 5m/s.

Q. The relative velocity of Ghabi relative to Athwal is..?

A) sqroot (50)m/s South East
B) sqroot (50)m/s North East
C) 5m/s North East
D) 5m/s South East

I tryed pythagoras theorm, and I got sqroot 50 South West, which isnt an answer. Whats the problem?

[xZero]

Lets look at an example, say that Athwal is walking to the west and Ghabi is stationary, relative to Ghabi, Athwal is walking to the west, however relative to Athwal, Ghabi is actually moving to the east (in Athwal's perspective, Ghabi is moving away from him) Hence it should be root50 South East.

[MissIraq]

Lets look at an example, say that Athwal is walking to the west and Ghabi is stationary, relative to Ghabi, Athwal is walking to the west, however relative to Athwal, Ghabi is actually moving to the east (in Athwal's perspective, Ghabi is moving away from him) Hence it should be root50 South East.

very confusing, would they ask these questions this year?

[xZero]

Not likely, but VCAA is too unpredictable :s. Another example is that Athwal is walking to the west relative to Ghabi, which is like saying Ghabi is walking to the east relative to Athwal. (If your still confused, try moving away from your computer screen, it can be said that your moving away from it or it is moving away from you. (This type of q is more like special relativity))

[MissIraq]

Not likely, but VCAA is too unpredictable :s. Another example is that Athwal is walking to the west relative to Ghabi, which is like saying Ghabi is walking to the east relative to Athwal. (If your still confused, try moving away from your computer screen, it can be said that your moving away from it or it is moving away from you. (This type of q is more like special relativity))

Ohh yes yes, haha ur funny, now it makes sence. By the way the question had diffrent names i just was so bored from the names they had, and changed them to Ghabi and Athwal. Ghabi means stupid in my language and Athwal means dopey    

[xZero]

ROFL, but it will never be as funny as the 'a cat was launched in a projectile motion' question I saw in a prac exam

[luffy]

ROFL, but it will never be as funny as the 'a cat was launched in a projectile motion' question I saw in a prac exam

LOL! That is hilarious! Haha.

I once saw a question in methods that said: A bird, flying in the air, realized his path was following a sine function with equation "blah blah."
Me: "Wow!!! I never knew birds could do that!"

[MissIraq]

ROFL, but it will never be as funny as the 'a cat was launched in a projectile motion' question I saw in a prac exam

Yea it was lol

ROFL, but it will never be as funny as the 'a cat was launched in a projectile motion' question I saw in a prac exam

LOL! That is hilarious! Haha.

I once saw a question in methods that said: A bird, flying in the air, realized his path was following a sine function with equation "blah blah."
Me: "Wow!!! I never knew birds could do that!"

Birds can do everything these days...At least I think they can