403.9 Negligence Negligence is the failure to use reasonable care, which is the care that a reasonably careful [designer] [manufacturer] [seller] [importer] [distributor] [supplier] would use under like circumstances. Negligence is doing something that a reasonably careful [designer] [manufacturer] [seller] [importer] [distributor] [supplier] would not do under like circumstances or failing to do something that a reasonably careful [designer] [manufacturer] [seller] [importer] [distributor] [supplier] would do under like circumstances.