I already have the solutions emailed to me from a D H Lawden textbook. I have trouble understanding the solution as the solution is not formatted properly, and the answer seems to be a little too advanced for me. I hope that some one can help me understand the problem. 1. The problem statement, all variables and given/known data A particle of mass m is moving in the plane Oxy under the action of a force f. Oxy is an inertial frame. Ox'y' is rotating relative to the inertial frame so that angle x'Ox = [itex] \omega [/itex] . (r,[itex]\theta[/itex])are the polar components of f, (ar,a[itex] \omega [/itex]) are the polar components of the particle's acceleration relative to Ox'y', v is the particle's speed relative to this frame and [itex] \theta [/itex] is the angle its direction of motion makes with the radius vector in this frame, obtain the equations of motion in the form: mar = fr +2m[itex]\omega [/itex] sin [itex]\theta[/itex] + mr[itex]\omega [/itex]2 mar = fr +2m[itex]\omega [/itex] sin [itex]\theta[/itex] + mr[itex]\omega [/itex]2 Deduce that the motion relative to the rotating frame is in accordance with the second law if, in addition to f, following forces are also taken to act on the particle: (i) m[itex]\omega [/itex]2r radially outwards (the centrifugal force, (iii) 2m[itex]\omega [/itex]v at right angles to the direction of motion (the Coriolis force) (iii) tranversely (The latter force vanishes if the rotation is uniform.) 2. Relevant equations Ok. So I'm looking at the solution and I don't understand how they progress from mathematical argument to the next mathematical argument. Maybe I'm weak on polar calculus. 3. The attempt at a solution I'm going to attach the solution later, since I'll have to scan that specific solution from the big solution set that comes from the book. As I mentioned before, the answer is not formatted properly, but it might still be clear enough for someone with better expertise to examine.