a 11 kg mass is moving at 4.9 m/s what is the magnitude of the net force needed to stop this mass at 9.3 seconds

Heya!!

For this, let's start calculating aceleration magnitude with formula:

                                                  Δ   Being   Δ

                                              V = Final velocity

                                              Vi = Initial velocity

                                              t  = time

                                              a = Aceleration

⇒ Let's replace according the formula:

⇒ Resolving:

Now, we have the aceleration, so lets applicate second law of Newton for calculate net force applicated:

                                                  Δ   Being   Δ

                                                  F = Force

                                                  m = mass

                                                a = Aceleration

⇒ Let's replace according the formula:

⇒ Resolving:

Result:

The net force applicated is of -4,73 Newtons.

Extra:

The minus represents when the force acts in the opposite direction to the acceleration of the body.

Good Luck!!

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.

answer and explanation;