A free falling body at some point on the trajectory had a speed of 20 m / s, and at another 40 m / s.

A free falling body at some point on the trajectory had a speed of 20 m / s, and at another 40 m / s. Determine the distance between these points. How long does it take for the body to pass it?

Data: V1 (speed at the first point of a certain trajectory) = 20 m / s; V2 (speed at the second point) = 40 m / s; free fall.

Constants: g (acceleration due to gravity) ≈ 10 m / s2.

1) Distance between points: ΔEp = ΔEk; m * g * Δh = m * (V2 ^ 2 – V1 ^ 2) / 2, whence Δh = (V2 ^ 2 – V1 ^ 2) / 2g = (40 ^ 2 – 20 ^ 2) / (2 * 10) = 60 m.

2) The duration of the path of 60 m: Δh = S = (V1 + V2) * t / 2, whence t = 2 * Δh / (V1 + V2) = 2 * 60 / (20 + 40) = 2 s.

Answer: The distance is 60m; the body moved for 2 s.