Power problem

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1. Oct 26, 2014

Kararr

1. "A car moves along a horizontal road against a resistance of 400 N. What is the greatest speed in kph that the car can reach if the engine has a maximum power of 16.0 kW?"

2. Relevant equations:
P= W/change in time
P= F x v (dot product)

Last edited: Oct 26, 2014
2. Oct 26, 2014

Staff: Mentor

W = F x v
is not correct

x is not the sign for a dot product
x is the cross product

3. Oct 26, 2014

Kararr

Sorry didn't know how to put the dot symbol that's why I put it in parentheses whoops

4. Oct 26, 2014

NTW

Besides, work is not force times velocity...

5. Oct 26, 2014

Staff: Mentor

The symbol mistake was incidental. The major problem is your formula W = F v
is not a valid formula. What formula for work does your textbook use?

6. Oct 26, 2014

Kararr

Edited: it's power=fv.

7. Oct 26, 2014

Kararr

Edited, p=fv

8. Oct 26, 2014

Staff: Mentor

So, can you use that equation to determine the "greatest speed" as the problem statement asks?