Its down below. Please help my daughter with the science please we've been working on it for like half an hour please please help

Which sound characteristic is not affected by the relative motion of an object

The combining of light nuclei is called blank. blank as in not actually blank. you know what im tryin to say.

In a heat engine if 1000 j of heat enters the system and the piston does 500j of work, what is the final internal energy of the system if the inital energy was 2000 j1.write the equation2.list out your known variables 3. plug the numbers into the equations4.solve 5.write your solution statement that includes initial energy and final energy added.