If a source of sound waves is rapidly approaching a person the sound heard by the person appears to have

Answer

Increasing frequency

Explanation

When the source of sound and the observer are moving towards each other the frequency tends to be increasing. Since wavelength is inversely proportional to the frequency, the wave decreases when the frequency increases.

These effect is called the Doppler effect named after the Austrian physicist Christian Doppler, who described the phenomenon in 1842

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.

massxgravity x heght=weightxheight= pe

4900=490xh

h=10