Physics

Problem

0.50\,\text{kg}

rock is dropped from rest from a cliff

4.0\,\text{m}

above the ground. Neglect air resistance. What is the speed of the rock just before it strikes the ground? a)

9.8\,\text{m}\!\cdot\!\text{s}^{-1}

6.3\,\text{m}\!\cdot\!\text{s}^{-1}

8.9\,\text{m}\!\cdot\!\text{s}^{-1}

19.6\,\text{m}\!\cdot\!\text{s}^{-1}