A 7,200-pound vehicle is driven at a speed of 30 miles per hour on a circular interchange of radius 180 feet. To keep the vehicle from skidding off course, what frictional force (in Ib) must the road surface exert on the tires? (Use 32 ft/sec for the acceleration due to gravity. Round your answer to two decimal places.)

A 7,200-pound vehicle is driven at a speed of 30 miles per hour on a circular interchange of radius 180 feet. To keep the vehicle from skidding off course, what frictional force (in Ib) must the road surface exert on the tires? (Use 32 ft/sec for the acceleration due to gravity. Round your answer to two decimal places.)