According to the doppler effect, if a car with a blowing horn is moving toward you, the pitch you hear will

B. Increase

Step-by-step explanation:

The closer together the crests, the higher the frequency (or pitch)

If a car with a blowing horn is moving toward you, the pitch sounds higher than the actual emitted frequency.

Step-by-step explanation:

In figure,

        V= speed of wave

         U= speed of car

When car moving towards you, then

Car travels a distance in time T = VT

 Wave travels a distance in time T = UT

From figure,

                    change in wavelength (λ') = VT - UT= T(V-U)

Now,

        V = λ' f'         (f' →frequency observed by you)

         f' = V ÷ λ' =

We know that

                      = f

Then,

        f' =  

        f' =

Hence, we can say that

           frequency increases as source moves toward you.

there are lots of ways.   pick's theorem tells us if the vertices are lattice points the area a is

a = b/2 + i - 1

where b is the number of boundary lattice points and i is the number of interior lattice points.

in the figure i count b=16, i=50 so

a = 8 + 50 - 1 = 57

let's try the shoelace formula.   the area is half the sum of the cross products of the sides.  

a(-2,6)   -2(2)-6(-5) = 26

b(-5,2)   -5(-3) - 2(-2) = 19

c(-2,-3) -2(-3) - (-3)(4) = 18

d(4,-3)   4(3) - (-3)(5) = 27

e(5,3)   5(3) - 3(1) = 12

f(1,3)     1(6) - 3(-2) = 12

a(-2,6)

each of the cross products is twice the area of the triangle with the associated side and one vertex the origin. so the area of abo=26/2=13.

area = (1/2) (26 + 19 +   18 + 27 + 12 + 12) = 57

that checks!