You may have noticed runaway truck lanes while driving in the mountains. These gravel-filled lanes are designed to stop trucks that have lost their brakes on mountain grades. Typically, such a lane is horizontal (if possible) and about 36.0 m36.0 m long. Think of the ground as exerting a frictional drag force on the truck. A truck enters a typical runaway lane with a speed of 50.5 mph50.5 mph ( 22.6 m/s22.6 m/s ). Use the work-energy theorem to find the minimum coefficient of kinetic friction between the truck and the lane to be able to stop the truck.

Respuesta :

Answer:

The  coefficient of kinetic friction  [tex]\mu_k =  0.724[/tex]

Explanation:

From the question we are told that

   The  length of the lane is  [tex]l =  36.0 \  m[/tex]

    The speed of the truck is  [tex]v  =  22.6\  m/s[/tex]

     

Generally from the work-energy theorem we have that  

    [tex]\Delta KE  =   N  *  \mu_k *  l[/tex]

Here N  is the normal force acting on the truck which is mathematically represented as

     [tex]\Delta KE[/tex] is the change in kinetic energy which is mathematically represented as

        [tex]\Delta KE =  \frac{1}{2} *  m *  v^2 [/tex]

=>     [tex]\Delta KE =  0.5  *  m *  22.6^2 [/tex]

=>      [tex]\Delta KE =  255.38m  [/tex]

        [tex]  255.38m =    m *  9.8  *  \mu_k *   36.0 [/tex]

=>     [tex]  255.38  =    352.8  *  \mu_k  [/tex]

=>   [tex]\mu_k =  0.724[/tex]