Determine the traction force of a car weighing 1700 kg, if it has acquired a speed of 20 m / s on the path of 20 m.

| January 11, 2021 | education

Determine the traction force of a car weighing 1700 kg, if it has acquired a speed of 20 m / s on the path of 20 m. Take the friction coefficient equal to 0.04.

m = 1700 kg.
S = 20 m.
V0 = 0 m / s.
V = 20 m / s.
μ = 0.04.
g = 10 m / s ^ 2.
Fт -?
Let us write 2 Newton’s law in vector form: F = m * a, where F is the resultant of all forces, m is the mass of the car, a is the acceleration of the car.
F = Ft + Ftr + m * g + N.
Ft + Ftr + m * g + N = m * a
ОХ: Fт – Fтр = m * a.
OU: N – m * g = 0.
Ft = m * a + Ftr.
Ftr = μ * N = μ * m * g.
Fт = m * a + μ * m * g = m * (a + μ * g).
a = (V ^ 2 – V0 ^ 2) / 2 * S = V ^ 2/2 * S.
Ft = m * (V ^ 2/2 * S + μ * g).
Ft = 1700 kg * ((20 m / s) ^ 2/2 * 20 m + 0.04 * 10 m / s ^ 2) = 17680 N.
Answer: the traction force of the car is Ft = 17680 N.



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