The body falls freely from a height of 10 m. At the same time, another body is thrown vertically downward

The body falls freely from a height of 10 m. At the same time, another body is thrown vertically downward from a height of 20 m. Both bodies fell to Earth at the same time. With what initial speed did you throw the second body?

Task data: h1 (fall height (path) of the first body) = 10 m; h2 (height of fall (path) of the second body) = 20 m; t (duration of the fall) = t1 = t2.

Constants: by condition g (gravitational acceleration) = 9.8 m / s2.

1) Duration of falling bodies: h1 = g * t ^ 2/2, whence t = √ (2h1 / g) = √ (2 * 10 / 9.8) = 1.429 s.

2) Initial velocity of the second body: h ^ 2 = Vn * t + g * t ^ 2/2 = V0 * t + h1, whence Vn = (h2 – h1) / t = (20 – 10) / 1.429 = 7 m /from.

Answer: The second body had to be thrown at a speed of 7 m / s.