If the soloist produces "x" decibels and the 10-person choir produces "y" decibels, combined they will produce "x+y" decibels.
The second choir has 90 additional singers, we base our description on the first choir. If a 10-person choir produces "x+y" decibels, then the 90 person choir produces 10 (x+y) decibels.
If the resistance of the Air is ignored, we can use the theory given by Galileo in which he warned that the thermal velocity of a body in free fall was given by

Where
g = Gravitational acceleration
t = time
As we can see the speed of objects in free fall is indifferent to the position that is launched (as long as the resistance of the air is ignored) or its mass.
Both bodies will end with the same thermal speed.
The broom handle that she have to balance if she hung a 400g mass from the end of the broom handle is 5.24m
This problem is centered on moment. Moment is the turning effect of a force about a point. It is expressed as:
Moment = Force× Distance
According to principle of moment, the sum of clockwise moment is equal to sum of anticlockwise moment at shown
M1d1 = M2d2
Given the following
M1 = 1.5kg
d1 = 1.4m
M2 = 400g = 0.4kg
d2 is required
Substitute
1.5(1.4) = 0.4d2
2.1 = 0.4d2
d2 = 2.1/0.4
d2 = 5.24m
Hence the broom handle that she have to if she hung a 400g mass from the end of the broom handle is 5.24m
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