The electric train, moving away from the stop, increases its speed to 72 km / h in 20 seconds.

| February 4, 2021 | education

The electric train, moving away from the stop, increases its speed to 72 km / h in 20 seconds. What is the acceleration of the electric train and what distance did it cover during this time?

V0 = 0 m / s.

V = 72 km / h = 20 m / s.

t = 20 s.

a -?

S -?

Let’s translate the units of measurement of the speed of movement in the units of the International SI system: V = 72 km / h = 72 * 1000 m / 1 * 60 min = 72000 m / 60 * 60 s = 72000 m / 3600 s = 20 m / s.

We find the acceleration of the train a by the formula: a = (V – V0) / t.

a = (20 m / s – 0 m / s) / 20 s = 1 m / s2.

We express the acceleration path of the train S by the formula: S = V0 * t + a * t ^ 2/2.

S = 0 m / s * 20 s + + 1 m / s2 * (20 s) ^ 2/2 = 20 m.

Answer: the acceleration of the train is a = 1 m / s2, the acceleration path is S = 20 m.



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