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A 1500-kg car locks its brakes and skids to a stop on a slippery horizontal road, leaving skid marks that are 15 m long. How much mechanical energy was dissipated as this happened? The coefficient of kinetic friction between the tires and the road is 400.40un.

Respuesta :

Answer:

[tex]E=88200\ J[/tex]

Explanation:

Given:

  • mass of car, [tex]m=1500\ kg[/tex]
  • distance of skidding after the application of brakes, [tex]d=15\ m[/tex]
  • coefficient of kinetic friction, [tex]\mu_k=0.4[/tex]

So, the energy dissipated during the skidding of car:

Frictional force:

[tex]f=\mu_k.N[/tex]

where N = normal reaction by ground on the car

[tex]f=0.4\ties 1500\times 9.8[/tex]

[tex] f=5880\ N[/tex]

Now from the work-energy equivalence:

[tex]E=f.d[/tex]

[tex]E=5880\times 15[/tex]

[tex]E=88200\ J[/tex] is the dissipated energy.