Average Power delivered to Engine

  • #1

Homework Statement

A 1000 kg car, starting from rest, accelerates uniformly to 15 m/s in ten seconds. Assume air resistance is constant at 300N. What is the average power delivered by the engine?

a. 13500 W
b.18000 W
c. 23000 W
d. 27000 W

Homework Equations

Average power = work/time
work = force(x) where x is magnitude of displacement.
force= mass x acceleration

The Attempt at a Solution

the force is equal to 1000 kg x 15 m/s = 15000

I don't know how to factor in air resistance, or arrive at a final answer. The answer is A...

Answers and Replies

  • #2
explain how you got the force of the car again...
  • #3
force = mass times acceleration
1000 x 15= 15000
  • #4
what is the units of the 15 value though
  • #5
ok.... i think i got it.... after getting the correct force (and units) times the displacement of x, (1800 * 75)/10.... gives the correct answer.