Which of the following is correct about the time period of a pendulum, whose length (length of thread) is 2 m and mass of whose bob (metallic ball) is 2 kg, when it is set in motion?

P = 2 * pi * (L / g)^1/2        period of simple pendulum

P = 6.28 * (2 / 9.8)^1/2 = 2.84 sec

if the thermos has a vacuum innner, then heat through conv currents and conduction are reduced = vacuum flask

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.