[sabre2th1]

http://www.xtremepapers.com/papers/E...e_20070117.pdf

Could a question similar to question 1 (check the above past paper) appear in exam papers? I am asking since the past paper I provided is from 2007 and I want to know whether these type of questions are still in the specification.. if yes, how exactly would you do these problems?

Thanks

EDIT: I was also wondering how many significant figures should one give an answer to (if its not stated in the question?)

[Killjoy-]

You have to apply Newton's second law.
If the lift is accelerating upwards then the box must be accelerating upwards at the same rate as it is in contact with the floor of the lift.

B cannot change, it represents the weight of the box.
Now if the box is accelerating upwards the magnitude of A must be greater than that of B.
Since B cannot change A must increase.

If the box is accelerating downwards the magnitude of B must be greater than that of A.
Since B cannot change A must decrease.

At constant speed the magnitude of A and B are the same.
In other words, they must be the same as when the box is stationary, so tick 'no change.'

I hope that makes sense.

I do Edexcel physics also. The style of question won't be in the spec but knowledge of Newton's second law certainly is!
Don't expect them to reuse the question but expect unfamiliar questions - so ones which aren't textbook style.