There is a small 100kg car with a motor that delivers 2000W. The frictional force always stays constant at 78.4N for the sake of this question. How much time does it take for the car to accelerate to 20m/s if starting from rest? and What distance will it travel before reaching 20m/s?

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anonymous · Answer

@thephysicsguy are you there? I'm willing to guide you through this problem.

anonymous · Answer

The first step is to put the given information in a format you can work with, and to find the equations that apply to this problem. In other words you 'translate' the words of the problem to a mathematical expression of the problem.

Of course we have $$\sum_{}^{}F=ma$$ 

where we know the Force and the mass, so from that we can find the acceleration. that's at least part of the solution.

anonymous · Answer

Sorry for the late reply, and how would you find the acceleration in a constant power problem? Isn't the instantaneous acceleration dependent on the instantaneous velocity?