Accelerating car, kinematics problem

[Jessicaelleig]

A 2.3 103 kg car starts from rest and accelerates along a horizontal roadway to +17 m/s in 21 s. Assume that air resistance remains constant at -500 N during this time. Find
(a) the average power developed by the engine and

(b) the instantaneous power developed at t = 15 s.

I am really confused about this. If you can help, I would appreciate it. Thanks!

 

[Stovebolt]

A 2.3 103 kg car starts from rest and accelerates along a horizontal roadway to +17 m/s in 21 s. Assume that air resistance remains constant at -500 N during this time. Find
(a) the average power developed by the engine and

(b) the instantaneous power developed at t = 15 s.

I am really confused about this. If you can help, I would appreciate it. Thanks!

I find a good place to start on any problem is to list the knowns and unknowns, then find equations that deal with those properties/units.

For instance, here you are given :
mass
initial velocity
final velocity
time
a force acting on the system

and you are looking for:
power

Keep in mind, power will have units in terms of Watts (or kW)
Power = Work / time
Work = Force * distance
Force = mass * acceleration


See if you can get started with that.