Question

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?

Answer 1

K.E = 463.04 k J

P = 23.14 Watt

Step-by-step explanation:

given,

mass of automobile = 1200 kg

velocity = 50 km/h

= 50 × 0.278

= 13.9 m/s

kinetic energy =
`(1)/(2)mv^2`

=
`(1)/(2)* 1200 * 13.9^2`

K.E = 115.93 k J

vehicle accelerated to velocity = 100 km/h

= 100 × 0.2778

= 27.78 m/s

kinetic energy =
`(1)/(2)mv^2`

=
`(1)/(2)* 1200 * 27.78^2`

K.E = 463.04 k J

work done = change in kinetic energy

= 463.04 - 115.93

= 347.11 J

Power =
`(work\ done)/(time)`

Power =
`(347.11)/(15)`

P = 23.14 Watt