- #1
TheRaiderNati
- 3
- 0
Homework Statement
A certain curve on a freeway has a radius of 200m and is banked at an angle of 25°. A 200-kg car moves around the curve at constant speed.
1. If the speed of the car is 35m/s, what friction force is needed to keep the car moving in a circle?
2. If the speed of the car is 35m/s, what normal force acts on the car?
3. If the speed of the car is 35m/s, what is the minimum value of the coefficient of friction?
Homework Equations
a[itex]_{cent}[/itex]=[itex]\frac{v^{2}}{R}[/itex]
F[itex]_{cent}[/itex]=m*a[itex]_{cent}[/itex]
The Attempt at a Solution
I have been attempting to solve this problem for about a week now but have but hopelessly stuck.
1. I tried to set up the equation so that the x-component of Weight plus the friction force (since the friction force points inwards) was equal to the Centripetal Force, like so:
F[itex]_{x}[/itex] = Wsin(25) + f = m*a[itex]_{cent}[/itex]
(Where f = friction force)
But I couldn't seem to get the right answer.
2.I figured that since the car has no vertical acceleration the sum of the net forces in the Y direction should equal to zero. In this case the only forces with Y components are the weight and normal force. Therefore:
F[itex]_{y}[/itex] = N - Wcos(25) = 0
However, this also produced an incorrect result.
3. I know that I can simply divide the force of friction by the Normal force to get the coefficient, so I guess I don't really need help on this one.
Answers were provided to me for these questions, but I still can't seem to get the same figures:
1. 2820N
2. 22900N
3. 0.123
3. 0.123
Thanks in advanced for any help.