- #1

- 12

- 0

5. Point Q is 3m above and 4m to the North of Point P. Ignoring friction how much energy does it take to move a 5kg sack of potatoes from point P to point Q?

These are multiple choice questions of the exam, so in the mark scheme it only says: A, B ....

The question paper can be found here:http://www.physics.ox.ac.uk/olympiad/Downloads/PastPapers/BPhO_PC_2004_QP.pdf

The markscheme can be found here:http://www.physics.ox.ac.uk/olympiad/Downloads/PastPapers/BPhO_PC_2004_MS.pdf

I am looking for an explanation as to why I am wrong

My current working:

We can use the Pythogorean Theorem , to determine that the box has to be moved a diagonal

5kg can give an approximate value of about 50N (e.g. gravitaional field about 10 ms^2)(Right/ Wrong and why?)

Finally we can use the equation W = fxd = 50N x 5m = 250J(Right/ Wrong and why?)

But in the marscheme it says the solution is C, namely 150J...

Why?

These are multiple choice questions of the exam, so in the mark scheme it only says: A, B ....

The question paper can be found here:http://www.physics.ox.ac.uk/olympiad/Downloads/PastPapers/BPhO_PC_2004_QP.pdf

The markscheme can be found here:http://www.physics.ox.ac.uk/olympiad/Downloads/PastPapers/BPhO_PC_2004_MS.pdf

I am looking for an explanation as to why I am wrong

My current working:

We can use the Pythogorean Theorem , to determine that the box has to be moved a diagonal

**distance**of 5m. (Right/ Wrong and why?)5kg can give an approximate value of about 50N (e.g. gravitaional field about 10 ms^2)(Right/ Wrong and why?)

Finally we can use the equation W = fxd = 50N x 5m = 250J(Right/ Wrong and why?)

But in the marscheme it says the solution is C, namely 150J...

Why?

Last edited: