The question is to rank the inertial forces, euler,coriolis and centrifugal in increasing order of strength, for a observer in the Earth' rotating frame, observing a body stationary in the UK. My thoughts are that coriolis = 2mw X (dr/dt), and so depends on the velocity so can only come into play when there is motion. A similar argument would hold for the euler force: m(dw/dt) X (dr/dt) . (Even without the dr/dt =0, my book says that dw/dt approximates zero, so this force would be zero anyway. This would give the order : centrigufal, corilios/euler - with coriolis and euler tied. However I'm not 100% sure dr/dt =0 - does this correspond to only translational motion? (The question does not mention any of the forces being of equal strength, so I assume I am wrong somewhere...) Thanks for your help guys !