Can someone pls explain how to answer these

Explanation:

Hook's law describes the force F a spring exerts on an object that is stretched or compressed by a distance x from its natural length and has spring constant k:

(1)

The force of gravity of an object with mass m and gravitational acceleration g is given by:

(2)

(a) To find the natural length l of the spring you can use the example 1 and 3 of the spring. Use equations 1 and 2 to get the following system of equations with two unknowns k and l:

To solve for k you can subtract the equations:

Now plug in k to solve for l:

(b) Now use Hook's law to find x:

(c) Do the same to find the mass m:

(d) Work is given by:

tube or goog with be a great resource to with that question

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.