Electric powerlines in electric Post hang very low in hot summer? Why?

Power cables hang or sag during summer is because of thermal expansion.

Explanation: Materials tend to expand when exposed to hot temperature. An example of this are the copper wires in transmission lines. They expand when the temperature is high and tends to sag or hang.

answer: at 24 february, 2014 the population gets twice of its initial population.

explanation:

since we have given that

the population for alpha city, t years after january 1, 2004 is given as

first we find out the initial population, i.e. t=0,

so, our quadratic equation becomes,

according to question, we have said that if the population has twice its initial population, then it becomes

so, time taken to reach this above mentioned population is given by

now, we know that time can't be negative so, we take t=9.149 years.

hence, at 24 february, 2014 the population gets twice of its initial population.