ATAR Notes: Forum
VCE Stuff => VCE Mathematics => VCE Mathematics/Science/Technology => VCE Subjects + Help => VCE Specialist Mathematics => Topic started by: chuck981996 on November 05, 2014, 11:17:16 pm
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Hi everyone,
From where are we supposed to draw the arrows for the "draw all the forces" questions? It seems in the examiners report that they just draw from the edges of the box - do they not care about, for instance, drawing the weight force from the centre of mass? Also, they draw friction forces in the middle of the side of the boxes, rather than along the surface. Is this because they want to ensure torque is 0? Should we do the same thing? (i.e. not like in physics?)
Also, when labelling forces, is it okay to simply use W for weight, N for normal, T for tension and F for friction? Or would it be better to use mg, N, T and muN - i.e. should we be more specific?
Sorry about all the questions, I just don't want to lose any marks due to anal examiners…
Thanks!
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Hi everyone,
From where are we supposed to draw the arrows for the "draw all the forces" questions? It seems in the examiners report that they just draw from the edges of the box - do they not care about, for instance, drawing the weight force from the centre of mass? Also, they draw friction forces in the middle of the side of the boxes, rather than along the surface. Is this because they want to ensure torque is 0? Should we do the same thing? (i.e. not like in physics?)
Also, when labelling forces, is it okay to simply use W for weight, N for normal, T for tension and F for friction? Or would it be better to use mg, N, T and muN - i.e. should we be more specific?
Sorry about all the questions, I just don't want to lose any marks due to anal examiners…
Thanks!
Torque is not a thing in specialist, ignore it. (on that, where you choose to draw your force vectors isn't going to affect the amount of torque on an object - that's like saying I drew a picture of myself and coloured it blue, so now I'm a smurf)
Force vectors should be drawn from the centre of mass. As long as all the force vectors are in written properly relative to each other, though, I don't think the examiners care - you could just draw them all originating from a completely different source, if you wanted to.
You can label forces however you want as long as it's obvious what each it - eg, don't use the gamma symbol to represent friction.