What is the average momentum of a 70-kg runner who covers 400 m in 50 s?

560 kg m/s

Explanation:

First of all, we have to find the velocity of the runner, which is given by  the ratio between the distance covered (400 m) and the time taken (50 s):

And now we can calculate the average momentum of the runner, which is equal to the product between the mass of the runner (70 kg) and its velocity, that we have previously calculated:

i don't know that i agree with that but what's the 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.