An accelerometer C is mounted to the side of the roller-coaster car and records a total acceleration of 2.8g as the empty car passes the bottommost position of the track as shown. If the speed of the car at this position is 185 km/h and is decreasing at the rate of 28 km/h every second, determine the radius of curvature p of the track at the position shown.

An accelerometer C is mounted to the side of the roller-coaster car and records a total acceleration of 2.8g as the empty car passes the bottommost position of the track as shown. If the speed of the car at this position is 185 km/h and is decreasing at the rate of 28 km/h every second, determine the radius of curvature p of the track at the position shown.