What are volume and density? how do they relate to each other?

Density= It is the mass divided by the volume. Density is defined as the mass per unit volume.

Volume= the quantity of three-dimensional space enclosed by a closed surface, for example, the space that a substance (solid, liquid, gas, or plasma) or shape occupies or contains.

Density expresses the proportional relationship between mass and volume of the substance. If the density of a particular substance is given in grams per milliliter, it indicates the number of grams present in 1 milliliter of that substance.

photocells convert light energy to electricity

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.