The body was thrown vertically downwards from a height of 120 m at a speed of 10 m / s.

The body was thrown vertically downwards from a height of 120 m at a speed of 10 m / s. How long will it take for the body to reach the Earth’s surface?

Data: h (drop height of the specified body) = 120 m; Vн (throwing speed) = 10 m / s; g (acceleration due to gravity) ≈ 10 m / s2.
The duration of the fall of the specified body is determined using the formula: S = h = Vн * t + g * t2 / 2.
Quadratic equation: 10 * t2 / 2 + 10 * t – 120 = 0 |: 5.
t2 + 2 * t – 24 = 0.
By Vieta’s theorem: t1 = -6 s (wrong); t2 = 4 s (true).
Answer: The fall of the said body lasted 4 seconds.