Acar moves in a straight line at 22.0 m/s for 10.0miles, then at 30.0 m/s for another 10.0miles. calculate the car’s average speed in m/s

25.38 m/s

Explanation:

We have a straight line where the car travels a total distance , which is divided into two segments :

(1)

Where

On the other hand, we know speed is defined as:

(2)

Where is the time, which can be isolated from (2):

(3)

Now, for the first segment the car has a speed , using equation (3):

(4)

(5)

(6) This is the time it takes to travel the first segment

For the second segment the car has a speed ,  hence:

(7)

(8)

(9) This is the time it takes to travel the secons segment

Having these values we can calculate the car's average speed :

(10)

(11)

Finally:

nah.   i'm just sleepy.

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.