1. at which point is the vertical velocity equal to zero? 2.during which part of the projectile's path does velocity increase?

#1

in projectile motion when object reached to the highest point then its velocity in vertical direction becomes zero

So its velocity in vertical direction is zero at POINT B

#2

During first half part of motion ball goes up high in air so its vertical speed will decrease due to gravity

while when it will drop back in next half where its vertical speed will increase

So its speed will increase between point B and C

an obstruction

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.