Answer:
The first law of thermodynamics is the law of conservation of energy. It states that energy is always conserved. ... To keep a machine moving, the energy applied should stay with the machine without any losses. Because of this fact alone, it is impossible to build perpetual motion machines.
Explanation:
Answer:
C. I'm pretty sure because I just took that test but I'm not sure
Answer:
1.2 billion hours or 137 thousand years
Explanation:
4 light-years, or 24 trillion miles. So, this trip would take 1.2 billion hours. There are 24 hours a day and 365.25 days per year, so this time in years is 137 thousand years.
Answer:
Sound is produced by an object vibrating and creating a pressure wave.
Explanation:
Best way is to study, pay attention in class. Something i have found very helpful is take notes. Writing things down is a very good way to remember content.