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Police investigators examining the scene of an accident involving two cars measure 79-meter long skidmarks of one of the cars which nearly came to a stop before colliding. The coefficient of kinetic friction between rubber and the pavement is about 0.82. Estimate the initial speed of that car assuming a level road.

Respuesta :

Answer:

[tex]v_i = 36.65 m/s[/tex]

Explanation:

As we know that friction force on the car during it applied brakes is given as

[tex]F_f = -\mu mg[/tex]

so the deceleration of the car is given as

[tex]a = -\mu g[/tex]

now we can use kinematics to find the initial speed of the car

[tex]v_f^2 - v_i^2 = 2 a d[/tex]

so we will have

[tex]0 - v_i^2 = 2(-\mu g)(d)[/tex]

now plug in all the data in it

[tex]v_i^2 = 2(0.82)(9.81)(79)[/tex]

[tex]v_i = 36.65 m/s[/tex]

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