Physics

Problem

A rock is thrown upward from the edge of a

40\,\text{m}

high cliff with an initial speed of

15\,\text{m s}^{-1}

. Neglect air resistance and take

g = 9.8\,\text{m s}^{-2}

. Determine the speed with which the rock hits the ground at the foot of the cliff. a)

37.2\,\text{m s}^{-1}

31.8\,\text{m s}^{-1}

23.6\,\text{m s}^{-1}

28.0\,\text{m s}^{-1}