Answer:
1963.93 Moles
Explanation:
-We know the standard conversion ratio for the volume of a mole is
Given volume of rooms as 
Convert the volume into liters:
#From our conversion ratio above, we get the volume of air molecules in moles as:

Hence, the volume of air molecules is 1963.93 Moles
Answer:
Only option A is correct
Explanation:
From the concept of Doppler effect, only speed matters. Thus, the faster a vehicle is moving, the closer together the sound waves get compressed and the higher the frequency. For example, for a very fast vehicle traveling at the speed of sound; the compressions are all right on top of each other. Thus, faster speed means closer compressions and higher frequencies. Hence, option only option A must be true because X is a higher frequency and so it must be going faster. The distance to the person will affect the volume but will not the pitch so Option B is not correct. Option C too is not correct because It doesn’t matter whether you are speeding up or slowing down, it only matters who is going faster. For example, from option c concept, if truck X was going 10 m/h and speeding up while truck Y was going 50 mph and slowing down, it would not meet the requirement that X has a higher frequency because only actual speed matters, not what is happening to that speed. Thus only option A is the correct answer
Moving a spring back and forth creates a longitudinal wave
Answer:
|Fr| = 50*√2 [N]
Explanation: (See Annex )
En el diagrama de cuerpo libre ( mostrado en el anexo) se ve que, al ser las dos fuerzas iguales (50 N) el paralelogramo formado para encontrar la resultante de las fuerzas (Fr) es un cuadrado, y la diagonal de ese cuadrado ( que es al mismo tiempo la hipotenusa del triangulo recto OPA ) es igual a:
Hipotenusa = |Fr| = √ (50)² + (50)²
|Fr| = √2* (50)²
|Fr| = 50*√2 [N]