پاسخ : حرکت
dx=kdt
az tarafi bar asase moadeleye dayere darim y=(r^2-x^2)^1/2
ba moshtaghgiri darim
dy=
kholase hosele nadaram be englisi benevisam khodetun hal konin kholase difransiel harkat ke sorat bashe be dast miad aslan ham lazem nist inghad khodetuno be zah mat bendazin(az fisaghores...