What is the maximum speed that a car can safely move on a horizontal road

What is the maximum speed that a car can safely move on a horizontal road at a bend with a radius of 81 m, if the coefficient of friction of the wheels on the road is 0.4?

R = 81 m.

g = 10 m / s2.

μ = 0.4.

Vmax -?

Let’s write 2 Newton’s law in vector form: m * a = Ftr + N + m * g.

ОХ: m * a = Ftr.

OU: 0 = N – m * g.

N = m * g.

The sliding friction force Ftr is determined by the formula: Ftr = μ * N = μ * m * g.

The centripetal acceleration a is expressed by the formula: a = Vmax ^ 2 / R.

m * Vmax ^ 2 / R = μ * m * g.

Vmax = √ (μ * g * R).

Vmax = √ (0.4 * 10 m / s2 * 81 = 18 m / s.

Answer: the maximum safe speed of the car when cornering is Vmax = 18 m / s.



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