Physics Question?

Question

I don't know any formulas to solve this problem. I have the answer in the back of the book. If ur answer match back of the book and u use a formula and explain how u got the answer i will leave best answer. Thanks!

If the coefficiend of friction between the tires of a car and the road is 0.300, what is the minimum stopping distance of a car traveling at 60.0 miles per hour?

Answer 1

Frictional force = FN (normal Force) * frictional coefficient.
FN is equivalent, in this case, to the weight of the car.

FN = mg (where g = 9.8)
Ff = .3 * m * g

When the frictional force acts against the car, it creates a negative acceleration.

Ff = .3 * m * g
a = Ff / m = .3g = 2.94 m/s^2.

Note: The key here is to understand that since you're given the frictional force, the mass of the car cancels out without you having to know it.

Now that you have the acceleration and the initial velocity, you can use Torricelli's equation to find distance:
Vf^2 = Vi^2 + 2ad
where Vf is the final velocity (0)
and Vi is the initial velocity (60 mph).

Answer 2

friction coefficient means that the car will lose 30% of its velocity every second. a coefficient of 1.0 is the most, that would make the car stop instantly, and 0.000 means no friction, and the car would never stop, like wet ice.