Answer:
897
Explanation:
Speed of the car, v = 126 km/h, converting to m/s, we have v = 35 m/s and
Radius of the curve, R = 150 mm = 0.15 m
The centripetal acceleration a(c) is given by the formula = v² / R so that
a(c) = 35² / 0.15
a(c) = 1225 / 0.15
a(c) = 8167 m/s²
The force that causes the acceleration is frictional force = µ m g, where
µ = coefficient of friction
m = the mass of the car and
g = acceleration due to gravity, 9.81
From Newton's law:
µ m g = m a(c) , so that
µ = a(c) / g
µ = 8167 / 9.81
µ = 897
Therefore, the coefficient of static friction must be as big as 897
