Assuming the top of the "Sponge Bob Square Pants Rock Bottom Plunge" is a parabolic curve of the equation shown in meters, find the normal acceleration of a rider at the top of the track moving at a velocity of 8.deltadeltadeltadelta m/s with respect to the track. Does the rider need to be held down by the restraints at that velocity? What would the velocity have to be for the rider to feel completely weightless?