The body falls freely from a height h without an initial velocity. In the last second it covers
August 31, 2021 | education
| The body falls freely from a height h without an initial velocity. In the last second it covers the distance S = 25 m. Find h.
1. The height that the body flew is found by the formula: h = g * t ^ 2/2, where g is the acceleration of gravity, equal to 10 m / s ^ 2.
2. According to the condition of the problem, an equation was drawn up:
10 * t ^ 2/2 – 10 * (t – 1) ^ 2/2 = 25;
5t ^ 2 – 5 * (t ^ 2 – 2t + 1) = 25;
5t ^ 2 – 5t ^ 2 + 10t – 5 = 25;
10t = 25 + 5;
10t = 30;
t = 30/10;
t = 3;
The flight time was 3 seconds.
3. If t = 3, then h = g * t ^ 2/2 = 10 * 3 * 3/2 = 45 meters.
Answer: the body falls from a height of 45 meters.
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