a) Masses, m1,m2,.....mk are at points P1,P2,.....Pk with position vestors P1,P2,.....Pk (these should be in bold) respectively. The position vector g of the centre mass is given by: (m1+m2+.....mk)g=m1,p1+m2p2+.....+mkpk(adsbygoogle = window.adsbygoogle || []).push({});

Find the position vector of the centre of mass of the masses 3,4, and 5kg placed at:

P1=(1,-1,1), P2=(2,-1,1) and P3=(-1,0,2) respectively.

Not sure how to do this

b) Determine the value of lambda that will make the following points coplanar:

(1,0,-3), (1,1,-2) and (lambda,-1,0).

Not sure how to do this either

c) Find a unit vector normal to the curve 2cosx-3e^x=y^2-1 at the point where x=-pi/4

Not sure how to do this as well

Any help would be great, even if its just a point in the right direction to start with

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# Homework Help: Vectors, poition vectors,

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