Ahigh speed train is traveling at a speed of 44.7 m/s when the engineer sounds the 415 hz warning horn. the speed of sound is 343 m/s. what is the wavelength of the sound, as perceived by the person standing at a crossing when the train is a) approaching and b) find the frequency when leaving the crossing?

Explanation:

Speed of the source of sound = v = 44.7 m/s

Speed of sound = V = 343 m/s

a) Apparent  frequency as the train approaches = f =  [V /(V -v) ] × f

= [343 / (343 - 44.7) ] × 415  = 477.18 Hz

Wave length =  λ = v / f = 343 / 477.18 = 0.719 m

b) Frequency heard as the train leaves = f ' =  [V / ( V + v) ] f

                                                                     = [343 / { 343 + 44.7 ) ] x 415

                                                                      = 367.2 Hz

Wavelength when leaving = v / f = 343 / 367.2 = 0.934 m

  1.the balanced   chemical equation is as below

cu +   2 ag(no)₃ → cu(no₃)₂   +2 ag

2.the   much silver   produced   is   50.9 g

step 1: find the   moles of cu

moles =   mass÷   molar mass

  from periodic table the molar mass of cu = 63.5 g/mol

moles is therefore = 15.00 g÷ 63.5 g/mol = 0.236   moles

step 2: use the mole ratio to determine the   moles of ag

from equation above   cu: ag   is 1: 2

therefore the moles of ag   =0.236   moles   x 2/1 =0.472   moles

step 3: find the mass   of ag

mass = moles x molar mass

from periodic table   the molar mass of ag =107.87 g/mol

mass   = 0.472   moles x 107.87 g/mol = 50.9 g

3.   the   much   silver   collected worth is   1.797 oz

  convert   50.9 g   to oz

that is   1 gram = 0.0353 oz

          50.9 grams =?   oz

by cross multiplication

={(50.9 grams x 0.0353 oz) / 1   gram}   =1.797 oz

i think the answer is a and b

i wish you luck