During t = 20 s, the body moved at a speed V1 = 20 m / s, during the next t2 = 20

univerkov | August 16, 2021 | education

During t = 20 s, the body moved at a speed V1 = 20 m / s, during the next t2 = 20 s – at a speed V2 = 30 m / s. What is the average body speed?

Initial data: the first section t1 = 20 s, V1 = 20 m / s; the second section t2 = 20 s, V2 = 30 m / s.

General solution of typical tasks: Vav. = S / t = (S1 + S2) / (t1 + t2), where S1 = V1 * t1 and S2 = V2 * t2.

Vav. = (V1 * t1 + V2 * t2) / (t1 + t2).

Let’s calculate: Vav. = (20 * 20 + 30 * 20) / (20 + 20) = (400 + 600) / 40 = 1000/40 = 25 m / s.

Special case: t1 = t2 and Vav. = (V1 + V2) / 2 = (20 + 30) / 2 = 50/2 = 25 m / s.

Answer: The average body speed is 25 m / s.

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