# Uniform Circular Motion Help

1. Oct 7, 2007

### Sean77771

1. The problem statement, all variables and given/known data

Part A) A car drives over a circular hill (hill radius is r). Is there a maximum speed that the car can have and still remain in contact with the road? If not, why not. If so, find an expression for the maximum speed.

Part B) Now, the car (with mass = 1000kg) enters a circular turn of radius, r=50m. The road is inwardly banked at an angle of 15 degrees. The road is wet so the coefficients of friction are: static u_s = 0.15, kinetic u_k = 0.08, rolling u_r = 0.02. Determine the range for the speed (v_min < v < v_max) that the car must maintain to stay on the circular turn.

2. Relevant equations

a = mv^2 / r
v = wr

3. The attempt at a solution

Very lost with this problem. I am assuming for part a that there is a maximum speed (this makes sense just thinking about it physically) but I don't know how to find this. I also can deduce that the greater the radius is, the greater the max speed will become. For part b, I tried drawing a free body diagram, but it seems to be in three dimensions because of the bank in the curve and I'm not sure how to account for that. Any help would be appreciated. Thanks.

2. Oct 7, 2007

### Sean77771

Please? I could really use some help.

3. Oct 7, 2007

### Sean77771

Even if it's just A or B?