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Homework Statement
A car is traveling at 50 mi / hr on a horizontal highway
a. If the coefficient of static friction between the road and tires on a rainy day is 0.100, what is the minimum distance in which the car will stop?
b. What is the stopping distance when the surface is dry and μs = 0.600?
Homework Equations
∑ f = ma
fs = (μs)(normal force)
Xf = Xi + (Vi)(t) + (1/2)at2
The Attempt at a Solution
Do not know where to start, please help.
Part a:
∑ Fx = ma - fs = 0
fs = (μs)(normal force)
∑ Fy = (normal force) = mg
ma = fs therefore ma = (μs)(normal force)
a = (μs)(normal force) / mass
Now: vf = 0
vi = 73.3 ft / second
Xf = Xi + Vi t + (1/2)at2
0 = 50 mi / hr + [ (0.100)(normal force) / mass ][t2]