Emily jogs 3 laps at the track to warm up. she jogs at 5 mph. then she runs 3
more laps at 7 mph. what is true about her average speed and her average
velocity?

Emily's average speed is 6 mph and her average velocity is zero.

Explanation:

We can calculate the average speed as:

s = (s₁ + s₂) / 2 = (5 mph + 7 mph ) /2 = 12 mph / 2 = 6 mph

s: average speed

s₁: speed in the first 3 laps

s₂: speed in the second 3 laps

And we can calculate the average velocity as:

v = (df - di) / t = (0 m - 0 m) / t = 0 m / t = 0 m / s

v: average velocity

df: final displacement

di: initial displacement

t: time

As Emily is finally in the same place, it doesn't matter the time to finish the 6 laps, we know that the displacement is zero so the average velocity is zero too.

change tension

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.