The minimum radius of the horizontal loop on the roller coaster to keep the centripetal acceleration below 29.0 m/s^2 is calculated using the formula r = v^2/a, yielding approximately 34.979 meters.
To calculate the minimum radius of the horizontal loop so that the centripetal acceleration does not exceed 29.0 m/s2, we use the formula for centripetal acceleration, which is a = v2/r, where a is the centripetal acceleration, v is the velocity, and r is the radius of the loop. Rearranging the formula to solve for r, we get r = v2/a. Substituting the given values, we calculate the minimum radius as r = (31.8 m/s)2 / 29.0 m/s2, which equals approximately 34.979 meters.
Therefore, the minimum radius of the horizontal loop should be about 34.979 meters to ensure that the centripetal acceleration does not exceed 29.0 m/s2.