A Car Travels in a Flat Circle of Radius R

Multiple Choice

A car travels in a flat circle of radius R. At a certain instant the velocity of the car is 20 m/s north, and the total acceleration of the car is 2.5 m/s² 37° south of west. Which of the following is correct?

A) R = 0.40 km, and the car's speed is decreasing.
B) R = 0.20 km, and the car's speed is decreasing.
C) R = 0.20 km, and the car's speed is increasing.
D) R = 0.16 km, and the car's speed is increasing.
E) R = 0.16 km, and the car's speed is decreasing.