Sleds with children begin to roll down the mountain and, evenly accelerating, in 19 seconds they pass 27 m.

Sleds with children begin to roll down the mountain and, evenly accelerating, in 19 seconds they pass 27 m. The weight of sleds with children is 87 kg. What is the acceleration of the sled? a = What is the resulting force on the sled?

t = 19 s.

S = 27 m.

m = 87 kg.

V0 = 0 m / s.

Frez -?

but – ?

We express the path S of the sleigh by the formula: S = V0 * t + a * t ^ 2/2, where V0 is the initial speed of the sleigh, t is the time the sleigh moves, and is the acceleration of the sleigh.

Since the initial speed of the sled is V0 = 0 m / s, the formula will take the form: S = a * t ^ 2/2.

We find the acceleration of the sled by the formula: a = 2 * S / t ^ 2.

a = 2 * 27 m / (19 s) ^ 2 = 2.8 m / s ^ 2.

According to Newton’s 2 law, the resulting force Fres, which acts on the body, is equal to the product of the body’s acceleration a by its mass m: Fres = a * m.

Fres = 2.8 m / s ^ 2 * 87 kg = 243.6 N.

Answer: the sled moves with an acceleration a = 2.8 m / s ^ 2, the resulting force Fres = 243.6 N. acts on them.