There are competitions in which pilots fly small planes low over the ground and drop weights, trying to hit a target. A pilot fl
ying low and slow drops a weight; it takes 3.0 s to hit the ground, during which it travels a horizontal distance of 170 m. Now the pilot does a run at the same height but twice the speed. How much time does it take the weight to hit the ground?
Each component is independent in two dimensional motion. This means that <em>how much time does something take to reach the ground when dropped is independent from any horizontal velocity</em>. If at one run a drop lasts 3s, at another run with twice the (horizontal) velocity and same height will also last 3s, no matter what.
The average walking speed for an adult would be around 6 m/s, and average leght of adult human legs is around 1m so the best answer of the given answers would be 7.9 m/s