The athlete runs 100m in 10s. The first 10 meters after the start, he runs with constant acceleration, the rest of the distance
The athlete runs 100m in 10s. The first 10 meters after the start, he runs with constant acceleration, the rest of the distance at a constant speed. Find acceleration for the first 10 meters and speed for the rest of the distance.
Task data: S (total length of the distance) = 100 m; t (total running time) = 10 s; S1 (first part of the distance) = 10 m.
1) Time in the first section:
1 equation: S1 = a * t12 / 2, whence we express: a = 2 * S1 / t1 ^ 2.
Equation 2: S2 = S – S1 = V * t2 = a * t1 * (t – t1) = 2 * S1 / t1 ^ 2 * t1 * (t – t1) = 2 * S1 / t1 * (t – t1) …
90 = 2 * 10 / t1 * (10 – t1).
90t1 = 20 * (10 – t1).
90t1 = 200 – 20t1.
110t1 = 200.
t1 = 200/110 = 1.818 s.
2) Acceleration on the first 10 meters: a = 2 * S1 / t1 ^ 2 = 2 * 10 / 1.8182 = 6.05 m / s2.
3) Speed at the rest of the distance: V = a * t1 = 6.05 * 1.818 = 11 m / s.