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?
1) R = 0.40 km, and the car's speed is decreasing.
2) R = 0.20 km, and the car's speed is decreasing.
3) R = 0.20 km, and the car's speed is increasing.
4) R = 0.16 km, and the car's speed is increasing.
5) R = 0.16 km, and the car's speed is decreasing.
Answer: 2