The cyclist traveled 1 half of the way at a speed of 10 m / s, 2 half at a speed of 15 m / s

| September 14, 2021 | education

The cyclist traveled 1 half of the way at a speed of 10 m / s, 2 half at a speed of 15 m / s What is the average speed of a cyclist?

S1 = S / 2.
S2 = S / 2.
V1 = 10 m / s.
V2 = 15 m / s.
Vav -?
The average speed of a cyclist’s movement Vav will be determined by the formula: Vav = S / t, where S is the entire path traveled by the body, t is the time of movement along the entire path.
The time of movement along the entire path t will add up with the time of movement in the first half of t1 and the time of movement in the second half of the path t2: t = t1 + t2.
t1 = S1 / V1 = S / 2 * V1.
t2 = S2 / V2 = S / 2 * V2.
t = S / 2 * V1 + S / 2 * V2 = S * (V2 + V1) / 2 * V1 * V2.
Vav = S / t = S / S * (V2 + V1) / 2 * V1 * V2 = 2 * V1 * V2 / (V2 + V1).
Vav = 2 * 10 m / s * 15m / s / (15 m / s + 10 m / s) = 12 m / s.
Answer: the average speed of a cyclist is Vav = 12 m / s.



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