A 950 kg car rounds an unbanked curve at a speed of 25 m/s. If the radius of the curve is 72 m, what is the minimum coefficient of friction between the car and the road required so that the car does not skid?

Compute the car's weight:

W = m g = (950 kg) (9.8 m/s²) = 9310 N

The net vertical force on the car is

∑ F = N - W = 0

so the normal force has magnitude

N = W = 9310 N

Then the friction force that keeps the car from skidding has magnitude F = µ N, where µ is the coefficient of friction, and it's friction that makes up the net horizontal force on the car. By Newton's second law, we have

F = m a

µ N = m v ² / R

µ (9310 N) = (950 kg) (25 m/s)² / (72 m)

µ ≈ 0.89

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weight of the box is given as

here this is placed on the inclined of angle 42 degree

now this weight will have two components one is along the incline other is perpendicular to it

so here we need to apply a force parallel to incline opposite to its component of weight

so here the component of weight is given as

here we have

so it requires 75 n force to move it upwards