Science:Math Exam Resources/Courses/MATH110/December 2014/Question 05 (b)/Statement

If a rock is thrown upward on the planet Mars with a velocity of 10 m/s, its height (in metres) above the ground level after $t$ seconds is given by $$h(t)=10t-2t^2.$$

(b) Find the velocity of the rock when it hits the surface.