Answer:
90m
Explanation:
Let g = 9.8 m/s2. The friction is the product of normal force and its coefficient, and normal force is equal to gravity
[tex]F_f = \mu N = \mu mg[/tex]
The acceleration caused by friction, according to Newton's 2nd law:
[tex]a_f = F_f / m = \mu g = 0.5 * 9.8 = 4.9 m/s^2[/tex]
For the friend to slide over, then the centripetal acceleration must be equal to friction acceleration.
Since you are driving at a constant speed of 21 m/s, then your maximum radius of curvature can be calculated using the following formula:
[tex]a_c = a_f = v^2/r = 4.9[/tex]
[tex]r = v^2/4.9 = 21^2/4.9 = 90 m[/tex]