In a Harry Potter movie, there is a big pendulum in the Great Hall that goes back and forth once every 18.9 s. What is the length of the pendulum (if it obeys Physics instead of magic)? (Unit = m)?

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.

hot magma rises and pushes up toward the lithosphere, and as it cools it cycles back down toward the core to be heated again.