An automobile has a mass of 1200 kg. What is its kinetic energy, in kJ, relative to the road when traveling at a velocity of 50 km/h? If the vehicle accelerates to 100 km/h in 15 seconds, what is the change in power required?

Respuesta :

Answer:

K.E = 463.04 k J

P = 23.14 Watt

Explanation:

given,

mass of automobile = 1200 kg

velocity = 50 km/h

             = 50 × 0.278

             = 13.9 m/s

kinetic energy = [tex]\dfrac{1}{2}mv^2[/tex]

                        =[tex]\dfrac{1}{2}\times 1200 \times 13.9^2[/tex]

        K.E = 115.93 k J

vehicle accelerated to velocity = 100 km/h

                                                    = 100 × 0.2778

                                                    = 27.78 m/s

kinetic energy = [tex]\dfrac{1}{2}mv^2[/tex]

                        =[tex]\dfrac{1}{2}\times 1200 \times 27.78^2[/tex]

        K.E = 463.04 k J

work done = change in kinetic energy

                   = 463.04 - 115.93

                   = 347.11 J

Power = [tex]\dfrac{work\ done}{time}[/tex]

Power =[tex]\dfrac{347.11}{15}[/tex]

P = 23.14 Watt