Traveling at a speed of 16.1 m/s, the driver of an automobile suddenly locks the wheels by slamming on the brakes. The coefficient of kinetic friction between the tires and the road is 0.720. What is the speed of the automobile after 1.30 s have elapsed? Ignore the effects of air resistance.

Question

issy14 · Answer

I figured out the distance = 20.93m. 
Please don't tell me the answer just guide me to the right answer.

issy14 · Answer

I know that it's asking me for the Vf, my problem is that I need the acceleration to figure it out but I don't have enough information to figure out the acceleration. I know the car keeps moving, it doesn't come to a full stop. So Vf is not 0m/s.

anonymous · Answer

Change in K.E = Workdone by Friction

anonymous · Answer

Use that, and you won't need acceleration to get your answer.

anonymous · Answer

$$\frac{ 1 }{ 2 }m(v _{f}^2 - v _{i}^2) = \mu mgx$$

anonymous · Answer

m cancels out; subst. x is distance in meters, and there you go...

anonymous · Answer

Distance cannot be 20.93m, because you get distance from the average speed in this situation.