3. A uniform metre rule is balanced at the 50 cm mark. Weights of 1.5 N and
3.0 N are hung from the 10 cm and 40 cm marks respectively, as shown in Fig. 2.1.
10 cm
40 cm 50 cm
80 cm
1.5N
3.ON
w
Fig. 2.1
A weight Whanging from the 80 cm mark balances the system.
Calculate
(a) the moment about the 50 cm mark of the 1.5N weight,

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.