The skier covered a 100 m slope in 20 s, moving with an acceleration of 0.3 m / s2.

| May 16, 2021 | education

The skier covered a 100 m slope in 20 s, moving with an acceleration of 0.3 m / s2. What is the speed of the skier at the beginning and at the end?

S = 100 m.

t = 20 s.

a = 0.3 m / s2.

V0 -?

V -?

When moving with constant acceleration, the movement of the body S is determined by the formula: S = V0 * t + a * t ^ 2/2, where V0 is the initial speed of the body, t is the time of movement, and a is the acceleration of the skier.

V0 * t = S – a * t ^ 2/2.

V0 = S / t – a * t ^ 2/2 * t = S / t – a * t / 2.

V0 = 100 m / 20 s – 0.3 m / s2 * 20 s / 2 = 2 m / s.

We express the speed of the skier at the end of the path V from the formula for acceleration: a = (V – V0) / t.

V = V0 + a * t.

V = 2 m / s + 0.3 m / s2 * 20 s = 8 m / s.

Answer: the initial speed of the skier was V0 = 2 m / s, the final speed became V = 8 m / s.



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