MEI M1 Jan 13 Question 7

This question makes no sense please someone help me!! http://www.mei.org.uk/files/papers/M1_Paper_Jan13.pdf
Much appreciated.
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Part iii) v) vi)

I've just done it, how far did yo get with those parts?

Still kind of stuck. I don't understand the idea of resolving horizontal or vertically. Or vertical equilibrium. If you could explain these it would help a huge.

So the whole idea with that is that perpendicular forces cannot act against each other, this bit is quite a simple concept, it's similar to how if you walk directly north you don't move any amount east or west.

now you have to apply this to forces, a horizontal force has no vertical component and vice versa, therefore they do not interact.

Back to the east west analogy, if you walk at an angle you are moving partly north and partly east/west and applying this to forces means that if a force isn't acting perpendicular to another force, these forces must be interacting.

To resolve with angles, if you want the horizontal component of a force you do Fcos(angle to the horizontal) or Fsin(angle to the vertical) and vice versa for vertical components.

Vertical equilibrium just means that the overall combination of vertical forces has an overall force (resultant force) of 0, this does not mean that the object isn't moving in the horizontal plane. (same with horizontal equilibrium)