Answer:
3.964 s
Explanation:
Metric unit conversion:
1 miles = 1.6 km = 1600 m.
1 hour = 60 minutes = 3600 seconds
75 mph = 75 * 1600 / 3600 = 33.3 m/s
22.5 mph = 22.5 * 1600/3600 = 10 m/s
Let g = 9.81 m/s2
Friction is the product of coefficient and normal force, which equals to the gravity
[tex]F_f = \mu N = \mu mg[/tex]
The deceleration caused by friction is friction divided by mass according to Newton 2nd law.
[tex]a = F_f / m = \mu mg / m = \mu g = 0.6 *9.81 = 5.886 m/s^2[/tex]
So the time required to decelerate from 33.3 m/s to 10 m/s so the wheels don't slide, with the rate of 5.886 m/s2 is
[tex]t = \frac{\Delta v}{a} = \frac{33.3 - 10}{5.886} = 3.964 s[/tex]
