An object in equilibrium has a net force of
. static equilibrium describes an object at
having equal and balanced forces acting upon it. dynamic equilibrium describes an object in
having equal and balanced forces acting upon it.

An object in equilibrium has a net force of zero  

Static equilibrium describes an object at  rest having equal and balanced forces acting upon it.

Dynamic equilibrium describes an object in  motion having equal and balanced forces acting upon it.

Explanation:

An object is said to be in equilibrium when a net force of zero is acting on it. When this condition occurs, the object will have zero acceleration, according to Newton's second law:

where F is the net force, m the mass of the object, a the acceleration. Since F=0, then a=0. As a result, we have two possible situations:

- If the object was at rest, then it will keep its state of rest. In this case, we talk about static equilibrium.

- If the object was moving, it will keep moving with constant velocity. In this case, we talk about dynamic equilibrium.

a electromagnetic waves

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.