#### elseany

##### Member

this is from the 2003 HSC Paper Q4:

(a) A particle P of mass m moves with constant angular velocity ω on a circle of

radius r. Its position at time t is given by:

x = r cos θ

y = r sin θ,

where θ= ωt.

(i) Show that there is an inward radial force of magnitude mr ω

i got as far as x''=-ω

but then i got stuck after that and i checked solutions and in their answer they stated that the force is m[sqrt(x''

edit: okay disregard, its hot and my room is small and im tired and sweaty and wasn't thinking @_@, i forgot that they were in different planes and i was thinking complex number vectors and oh dear god i confused my self a hell of a lot :<

(a) A particle P of mass m moves with constant angular velocity ω on a circle of

radius r. Its position at time t is given by:

x = r cos θ

y = r sin θ,

where θ= ωt.

(i) Show that there is an inward radial force of magnitude mr ω

^{2}acting on P.i got as far as x''=-ω

^{2}x and y''=-ω^{2}ybut then i got stuck after that and i checked solutions and in their answer they stated that the force is m[sqrt(x''

^{2}+ y''^{2})], i get the whole f=ma thing, but i dont understand why they had to use the right angle triangle in this and they didnt just sum the acceleration components like they do with force. i mean isnt acceleration just f/m and if m is constant then its essentially the same as f... why can we sum forces but not acceleration? :<edit: okay disregard, its hot and my room is small and im tired and sweaty and wasn't thinking @_@, i forgot that they were in different planes and i was thinking complex number vectors and oh dear god i confused my self a hell of a lot :<

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