A 600-kg car is going over a curve with a radius of 120 meters that is banked at an angle of 25 degrees with a speed of 30 meters per second. The coefficient of static friction between the car and the road is 0.3. What is the normal force exerted by the road on the car?

a) 7240 N
b) 1590 N
c) 5330 N
d) 3430 N
e) 3620 N

Note: The speed is not Vmax (roughly 32 m/s). I've been working under the assumption that mgcos(theta) will be increased by the frictional component acting downward. I simply can't seem to get the solution.

Question

A 600-kg car is going over a curve with a radius of 120 meters that is banked at an angle of 25 degrees with a speed of 30 meters per second. The coefficient of static friction between the car and the road is 0.3. What is the normal force exerted by the road on the car?

a) 7240 N
b) 1590 N
c) 5330 N
d) 3430 N
e) 3620 N

Note: The speed is not Vmax (roughly 32 m/s). I've been working under the assumption that mgcos(theta) will be increased by the frictional component acting downward. I simply can't seem to get the solution.

kunal · Answer

i think it will be mgcos(theta) only frictional force does not affevt the normal reaction from the road but will contribute in the total normal force on the body...

anonymous · Answer

Strange. I posted this question a few weeks ago. The trick, evidently, is that the problem gives you too much information. 
Instead of "adding" the coefficient of friction into your system of equations, solve the two equations in general. You will get answer choice A) 7240.

anonymous · Answer

Here is the answer.