Adog whistle uses a frequency higher than humans can normally hear. a pet owner wants to test his dog whistle. the owner has a drive a car and blow the whistle while he stands on the sidewalk. in which direction should the driver drive so that the pet owner can hear it and why?

The driver should drive away from the pet owner.

Explanation:

The apparent frequency reduces when the source and listener are relatively moving away from each other and increases when they are moving towards each other. This from the Doppler's effect.  Thus, driver should drive away from the pet owner so that the apparent frequency decreases and can be heard by the pet owner.

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.