How would present-day earth be different if it weren’t dynamic

If the continents were eroded completely into the oceans there would be no continents and no land left. ... Without plate tectonics that push the continents up the erosion would result in the continents disappearing under the surface of the oceans.

a longitudinal wave moves energy that is to the direction of the wave’s movement. - true

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.