TomRed's blog & stuff

Update: this guy does solutions (including M1 solutions) on YouTube. He might be your last hope.

For those of you that don’t do mechanics, walk away, nothing to see here. As explained in the A-level stuff section to your top right I don’t have a maths section, so I’ll put this material here.

Basically, in mechanics, almost every paper asks a question or two about mathematical modelling, and requires a bit of common sense and awards a mark or two. I don’t have common sense, so if you’re on mutual grounds with me then you might want to know the general answers, and they are as follows:
• If it asks about how you’ve used the fact that the string is light, tensions will be the same for the two particles.
• If it asks about how you’ve used the fact that the the string is inextensible, acceleration will be the same for the two particles.
• Asking about what it means for the string to be light, mention that it has no weight.
• When asking about how a model is unrealistic or what refinements can be made for kinematics, mention air resistance or possibly the ‘spin’ of the particle (use your head).
• If it asks what it means that a beam is uniform, the weight acts at the midpoint of the beam.
• If it asks what it means for something to be a particle on a beam, mention that its weight acts precisely at that point.
• When asking about what it means for the plank or beam or whatever to be a rod, it means it’ll remain a straight line/rigid.

I think that’s correct, don’t kill me if I’m wrong. I got them from the mark schemes, and compiled them on this document: