- #1

razidan

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**I am tutoring a student, and this question was given to her. I believe it is not clearly stated and wanted your opinion. I hope this is the best forum for this.**

1. Homework Statement

1. Homework Statement

What is the minimum wattage required to accelerate a car of mass m (don't remember the value) from 0 to 28 m/s in 6 seconds, on an incline of 10 degrees, with a constant drag force of 150N.

## Homework Equations

## The Attempt at a Solution

The solution, as was given by the teacher was: ##P=F\cdot\frac{\Delta x}{\Delta t}## where F is the net force (pointing downhill), ##|F|=F_{drag} +mgsin(\alpha)##, and the average speed can be determined from kinematics equations.

I believe this is wrong. the question states that car is accelerated to 28 m/s. meaning, at the instant of t=6 sec, it has a velocity of 28 m/s, and thus some engine power went to kinetic energy. then the minimum wattage needed would have to have an addition of ## \frac{\frac{mv^2}{2}}{6 sec}## to the power that was calculated above.

Am i correct?

Thanks,

R

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