AQA Physics A - PHYA4 (11/06/12) - Exam thread

Who is arguing that tension isn't maximum at top and bottom? I didn't even see a question 5... ****, how many marks was it?

I saw it with my own eyes. You must of missed it!

The front paper had 6 boxes. Q12345 and total. 4 boxes would imply that there were 3 questions only.

I think you have alot of your forces muddled up. Read my post and see if you have any problems after that, i'd be happy to help.

This guy's clearly just made two accounts to mess with our heads

Nice try.
Also noone was arguing about when tension is highest, why did you bring that up and what question what it? I can't remember needing it.

When considering the mass-spring system:

since the resultant force is =ma.

and since a is 0 at equilibrium, then the resultant force is also 0 at equilibrium. Your forces seemed muddled in the picture, as through the centre the spring stilll has tension on the mass, and this tension is equal to the weight. Its just the its got max v at that point so it keeps on moving.

I am a 100% sure there wasn't any emf question or a question 5. :O
I looked over three times! What the hell?

The mini heart attack you got when Rennit said there was a question after the 6 marker

It asked where acceleration was at a max. Not tension.

It asked where acceleration was at a max. Not tension.

There wasn't, he was messing with everyones head. The 6 marker which i missed anyway was the last question.

The left pic is when it's at the middle, where only weight is acting on it.

yes, but that isnt the case. The equilibrium position is when the tension is equal to the weight. The equilibrium position has acceleration of 0, therefore a resultant force of 0.

You seem to think that the equilibrium position has no force from the spring. perhaps it will help if you think about when a mass is attached to a spring and allowed to rest. It is in extension at the equilibirum position, but is not moving. This means the resultant is 0 at that position because T=mg.

Oh yes silly me, I suppose acceleration is provided by a mystical force that is unrelated to the spring.

The tension is the force that supplies the acceleration.


Seriously, some of you guys don't have a clue.

yes, but that isnt the case. The equilibrium position is when the tension is equal to the weight. The equilibrium position has acceleration of 0, therefore a resultant force of 0.

You seem to think that the equilibrium position has no force from the spring. perhaps it will help if you think about when a mass is attached to a spring and allowed to rest. It is in extension at the equilibirum position, but is not moving. This means the resultant is 0 at that position because T=mg.