The correct answer to this question is this one:
By definition, if a molecule is composed of two hydrogen atoms and one oxygen atom, that molecule is a water.<span> In fact, the structure of water is written as H20, which signifies that two hydrogen (H) atoms and one oxygen (O) atom make up the molecule.</span>
1) If the object changes directions with the same speed, it will be changing its velocity, because velocity is a vector, which depends on both magnitude and direction. Speed is just magnitude regardless of direction.
2) Rotational motion.
Answer:
C)Before leaving for their trip, turn the central heating system off, along with lights and electrical household appliances.
Explanation:
Although, the other three options will also reduce their electricity bill but they do not explain why Mr. Hernandez's family got same electricity bill as last year even though this time they were not home for one and a half week. Also, A), B) and D) ideas are not reasonable.
So, the only conclusion is that even when they were on a vacation. the electrical appliances in their home were on. That's why the bill remained the same.
The idea of turning the central heating system off, along with lights and electrical household appliances before they leave for the trip will help reduce the energy usage. Also, it is reasonable.