Note that , and by the chain rule, . Note that the set of possible velocity vectors forms a vector space. If and are two paths through the origin, then so is and the velocity vector of this path is . Similarly, if is a scalar, then the path has velocity vector . It makes sense to distinguish the velocity vectors at different points. In physics, the set of all velocity vectors gives all possible combinations of position and momentum, and is called phase space.
Often ribs are boiled or oven-steamed before grilling to help tenderize the meat. To oven-steam ribs, place ribs in a large baking pan, fill with about 1 inch of water, cover with aluminum foil and bake for about 50 minutes in a 350-degree oven. The recipe here includes instructions on how to boil ribs before grilling.
Slow Roasting the Ribs. Another way to precook ribs for the grill is in your oven or slow cooker. Season the ribs ahead of time with a dry rub made from herbs and spices or dried spicy dip mix, then place them on a sheet pan or in your slow cooker. Use the low setting on the slow cooker, or preheat your oven to 250 degrees Fahrenheit. Slow-roast the ribs until they are nearly fork-tender, usually for 2 1/2 to 4 hours depending on the size of the rack. Transfer the ribs to your grill, and finish them over direct heat with your favorite sauce.