Answer:
The coefficient is 0.90
Explanation:
Drawing a diagram makes thing easier, we will assume that the acceleration tends to zero because it start barely moving.

A. microscopes !!!!!!!!!!
The image formed by a plane mirror is virtual, upright and the same size with the actual object. The upright image of an object in a plane mirror is can be found on the other side of the mirror which is why it is also virtual.
So, the angle between two vectors having equal magnitude is equal to 120º.
Explanation:
<h2>:) Correct me if I'm wrong...</h2>
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.