Science:Math Exam Resources/Courses/MATH102/December 2011/Question 07 (ii)/Statement

A particle is moving in the (x,y)-plane along the curve $y=x^{2}$. As it passes through the point P = (2, 4), its y coordinate changes at a rate of 8 units/sec.

ii) What is the rate of change of the particle's distance $D(t)$ to the origin at this instant?