Does the weight of an item determine cooking time?

I am a bit baffled by some of the cooking guides for roasts.  I have a 5lb pork, boneless roast, ready to go.  The recipes I see on the app and in most temperature guides look like they are geared to 1-2lbs.  Is there a simple calculation I can use to determine time based on weight for roasts?

The minimum cooking time for any cut of meat is normally based on thickness not weight. The thicker the roast the longer it will take to reach a consistent temperature throughout.