Answer:
KE2 = 2 KE1
1/2 M V2^2 = 2 * (1/2 M V1^2)
V2^2 = 2 V1^2
V2 =
V1
Since momentum = M V the momentum increases by 
a una velocidad de
22 m/s, quien lo golpea y devuelve en la misma
dirección con una velocidad de 14 m/s. Si el
tiempo de contacto del balón con la jugadora es
de 0,03 s, ¿con qué fuerza golpeó la jugadora el
balón?
21 Una bala de 0,8 g, está en la recámara de un rifl e
cuando se g
working...
Sound wave needs medium to travel
as energy which travels in this wave is because of transfer from one particle to another particle
If there is no medium then energy can not be transferred and sound wave will not travel
so in vacuum we can not listen sound
similarly here air is removed it means there is no medium inside the jar to travel the sound and hence we can not hear it
Option B is correct
Without air, the sound waves cannot travel to the ear.
The answer for this question is Control Variable because it doesn’t change throughout the experiment.