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posted by  Momar on 7/15/2008 10:54:20 PM  |  status: Live  

Power Questions

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Question Details:
A car of weight 1.2 x 104 Newtons accelerates uniformly from rest to 27m/s in 6 seconds along a level stretch of road. Ignoring friction, determine the average power required to accelerate the car.
 
I've been stuck on this problem for a while and it's REALLY bugging me. Im not quite sure how to approach it and what the final answer would be. You help would really be appreciated.
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posted by Cdutch88 on 7/15/2008 11:10:39 PM  |  status: Live
Asker's Rating: Lifesaver   
Momar's comment:
"Thank you, I can see the points I was missing"
Response Details:
Power = Work / Time = Force * Distance / Time = Mass * Acceleration * Distance / Time

We know that Mass = 1.2 x 104 Newtons
We know that Time = 6 seconds

Acceleration = (vf - vi) / t = (27 - 0) / 6 = 4.5 m/s2

Distance can be calculated as well:
Distance = vi*t + 1/2 * a * t2 = 0*6 + 1/2 * 4.5 * 62 = 81 m

Putting it all together, we have
Power = 1.2 x 104 * 4.5 * 81 / 6 = 729000 W

Hope that helps!
Lifesaver means I answered your question correctly and error-free. Please rate accordingly, I'd be super grateful! Thanks!
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