Question 13 and 14 on Motion

[qwertyda2nd]

Do you think that if i got 100N/m for Q13 that they would mark Q14 consequentially as I used that answer to find the change in energy (that i got =0)?

[Stormer]

It seems a lot of people have got 100N/m for Q13. I put 50N/m but i'm not sure that's correct now.

[Akirus]

It seems a lot of people have got 100N/m for Q13. I put 50N/m but i'm not sure that's correct now.

Where does 100N/m come from..?

[Stormer]

Energy calculations apparently. Physics teacher at my school had 100N/m as well.

[Akirus]

Energy calculations apparently. Physics teacher at my school had 100N/m as well.

Incorrect assumption, since the gravitational energy is not necessarily transformed completely into elastic potential energy. It's 50N/m.

[Stormer]

Fantastic.

They reasoned that it had something to do with the force not being constant. Wouldn't have a clue.

[googoo]

which school?

[Juddinator]

I had 50N/m as well. Didn't think twice about it tbh....

[Stormer]

which school?

Essendon Grammar

[Stroodle]

I'm confident that it's 50 and 4. My physics teacher is seriously amazing, and this is what he got.

[Akirus]

I'm confident that it's 50 and 4. My physics teacher is seriously amazing, and this is what he got.

Kyzoo's teacher is the head examiner (at least, that's what he said) and he said it's 4J, whatever that is worth.

It doesn't matter how it's pulled down, because it's the weight force that is maintaining the extension the final position.

[Blakhitman]

I'm confident that it's 50 and 4. My physics teacher is seriously amazing, and this is what he got.

Kyzoo's teacher is the head examiner (at least, that's what he said) and he said it's 4J, whatever that is worth.

It doesn't matter how it's pulled down, because it's the weight force that is maintaining the extension the final position.

Head assessor probably, examiners aren't allowed to teach

[kyzoo]

>.< Assistant chief head assessor lol, and that doesn't mean he's right 0.o everyone makes mistakes (our physics class are full of examples of this haha)

[Akirus]

I'm confident that it's 50 and 4. My physics teacher is seriously amazing, and this is what he got.

Kyzoo's teacher is the head examiner (at least, that's what he said) and he said it's 4J, whatever that is worth.

It doesn't matter how it's pulled down, because it's the weight force that is maintaining the extension the final position.

Head assessor probably, examiners aren't allowed to teach

Ah, right. I thought they were the same thing anyway.

I don't see how it's wrong though.

[Ball Lightning]

100 comes from this which i posted in another thread:

I equated the energy at the top unstretched with the energy .4m below, the spring energy.

This gave:

mgh=(1/2)*k*x^2

which came out to k=100

As there is no loss in energy (as the hand does not take away from either sides energy)

8=8 Therefore there is a 0 change in energy, and it is conserved.

From a brief discussion we had with our teacher he agreed with us about this answer.