Does the air in a balloon have masd

An architect plans to use solar energy to heat the next house he designs. what principle of absorption and infrared energy can be applied to the design of the new house? how could she apply to those principals?

Which statements best describe energy? check all that apply. the total amount of energy in the universe remains constant. the total amount of energy in the universe changes constantly. energy cannot be converted from one form to another. energy can be converted from one form to another. energy cannot be created or destroyed. energy can be created or destroyed.

Jaylen is a championship runner of the school's track team. during one of his trials, his speed was measured at 15.1 m/s. find jaylen's kinetic energy during that trial if his mass is 54.6 kg.