A traveler at Newark airport pulls his 294N suitcase with constant velocity to the check-in counter applying a force of 159N at an angle of 37 degrees with the horizontal. Calculate the Normal force, frictional force and the coefficient of friction between the suitcase and the airport floor.

N = 198.3 N,  fr = 126.98 N and    μ = 0.64

Explanation:

For this exercise we must use the translational equilibrium condition.

Let's set a reference system with the x-axis horizontally and the y-axis vertical. Let's use trigonometry to decompose the applied force

      cos θ = Fₓ / F

      sin θ = F_y / F

      Fₓ = F cos θ

      F_y = F sin θ

      Fₓ = 159 cos 37 = 126.98 N

      F_y = 159 sin 37 = 95.69 N

Y axis  

    N + F_y - W = 0

    N = W - F_y

    N = 294 - 95.69

    N = 198.3 N

X axis

    Fₓ -fr = 0

     Fₓ = fr

     fr = 126.98 N

the expression for the friction force is

       fr = μ N

       μ = fr / N

       μ = 126.98 / 198.3

       μ = 0.64

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