Modern roller coasters have vertical loops shaped like the one shown below: minimum D B Utop C maximum A The radius of curvature is smaller at the top than on the sides which helps to ensure that the centripetal acceleration at the top (pointing downwards) is greater than g, keeping riders pressed into their seats. What is the speed of the roller coaster at the top of the loop if minimum 14.5 m and the downward acceleration of the car is 1.4 g? Include units as appropriate.