You throw a ball downward from a window at a speed of 2.0m/s. The ball accelerates at 9.8m/s^2. How fast is it moving when it hits the sidewalk 2.5m below?

Question

You throw a ball downward from a window at a speed of 2.0m/s.  The ball accelerates at 9.8m/s^2.  How fast is it moving when it hits the sidewalk 2.5m below?

Anonymous · Answer

initial speed: 2 m/s a: -9.8 m/s^2 s: -2.5 m final speed: ? Vf^2 - Vi^2 = 2as v^2 - 2^2 = 2•-9.8•-2.5 v^2-4 = 49 v^2 = 53 final speed is approx. 7.28