Physics

Problem

A ball is thrown vertically upward with a speed of

28\,\text{m/s}

. After how much time will it again be exactly

30\,\text{m}

above the point of projection on its way down? (Take

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

.) a)

1.43\,\text{s}

5.72\,\text{s}

4.29\,\text{s}

2.86\,\text{s}