The Student Room Group
Uni students - Complete our survey >>
Uni students - Complete our survey >>
Uni students - Complete our survey >>

Elastic Springs and string Edexcel FM1

I don't understand the mark scheme to this elastic springs question

I have attached my working the mark scheme and the original question.

Thanks
00072b8eb1c80c2a870bce12b7b07a29.png246.4KB
61bf83f9e7230c7e8de66f21dc047928.png10.8KB
2153d575742c9cdcc6b342511da56dd0.png33.7KB
Original post by thotproduct2
I don't understand the mark scheme to this elastic springs question

I have attached my working the mark scheme and the original question.

Thanks


You have a small typo in your working - should be l2−x2l^2-x^2 in the brackets on the left.

I suspect that the markscheme assigned x on the other side of the eqilibrium position, treating it as an extension rather than a compression.

Your equation will work and gives x=l/2 as one answer, and hence distance moved is 3l/2.
Original post by ghostwalker
You have a small typo in your working - should be l2−x2l^2-x^2 in the brackets on the left.

I suspect that the markscheme assigned x on the other side of the eqilibrium position, treating it as an extension rather than a compression.

Your equation will work and gives x=l/2 as one answer, and hence distance moved is 3l/2.


Thank you!!
Original post by thotproduct2
Thank you!!


Original post by ghostwalker
You have a small typo in your working - should be l2−x2l^2-x^2 in the brackets on the left.

I suspect that the markscheme assigned x on the other side of the eqilibrium position, treating it as an extension rather than a compression.

Your equation will work and gives x=l/2 as one answer, and hence distance moved is 3l/2.

Can an extension situation actually be used in a question like this surely you wouldnt get the 3l/2?
Original post by thotproduct2
Can an extension situation actually be used in a question like this surely you wouldnt get the 3l/2?


It can be used and it does work. With the markscheme we get x= -l/2, and so total distance is

l - (-l/2) = 3l/2, as required.

Quick Reply

Related discussions

Latest

Trending

Trending

Articles for you