A car with a mass of 1.50x10^3 kg starts from rest and accelerates to a speed of 18.0m/s in 12.0 s. assume that the force of resistance remains constant 400.0n during this time. what is the average power developed by the car's engine.

Question

Paula Poole

Physics

5 February, 00:49

A car with a mass of 1.50x10^3 kg starts from rest and accelerates to a speed of 18.0m/s in 12.0 s. assume that the force of resistance remains constant 400.0n during this time. what is the average power developed by the car's engine.

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Answers (1)

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Esmeralda Harrell · Answer 1

The first thing you should know for this case is the definition of distance.

d = v * t

Where,

v = speed

t = time

We have then:

d = v * t

d = 9 * 12 = 108 m

The kinetic energy is:

K = ½mv²

Where,

m: mass

v: speed

K = ½ * 1500 * (18) ² = 2.43 * 10 ^ 5 J

The work due to friction is

w = F * d

Where,

F = Force

d = distance:

w = 400 * 108 = 4.32 * 10 ^ 4

The power will be:

P = (K + work) / t

Where,

t: time

P = 2.86 * 10 ^ 5/12 = 23.9 kW

answer:

the average power developed by the engine is 23.9 kW