When one person shouts at a football game, the sound intensity level at the center of the field is 58.4 dB. When all the people
shout together, the intensity level increases to 102 dB. Assuming that each person generates the same sound intensity at the center of the field, how many people are at the game?
2 answers:
Answer:
The number of people at game are approximately 22909
Explanation:
Given data
When one person shout
When n number of person shout together
The sound intensity level during one person shout is given by:
The sound intensity level during n number of person shout is given by:
Since each person generates same sound intensity and hence total number of persons can be determined as
Hence
The number of people at game are approximately 22909
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Answer:
a) W = 46.8 J and b) v = 3.84 m/s
Explanation:
The energy work theorem states that the work done on the system is equal to the variation of the kinetic energy
W = ΔK = -K₀
a) work is the scalar product of force by distance
W = F . d
Bold indicates vectors. In this case the dog applies a force in the direction of the displacement, so the angle between the force and the displacement is zero, therefore, the scalar product is reduced to the ordinary product.
W = F d cos θ
W = 39.0 1.20 cos 0
W = 46.8 J
b) zero initial kinetic language because the package is stopped
W - =
-K₀
W - fr d= ½ m v² - 0
W - μ N d = ½ m v
on the horizontal surface using Newton's second law
N-W = 0
N = W = mg
W - μ mg d = ½ m v
v² = (W -μ mg d) 2/m
v = √(W -μ mg d) 2/m
v = √[(46.8 - 0.30 4.30 9.8 1.20) 2/4.3 ]
v = √(31.63 2/4.3)
v = 3.84 m/s
Answer:
The initial acceleration of the 59g particle is
Explanation:
Newton's second laws relates acceleration (a), net force(F) and mass (m) in the next way:
(1)
We already know the mass of the particle so we should find the electric force on it to use on (1), the magnitude of the electric force between two charged objects by Columb's law is:
with q1 and q2 the charge of the particles, r the distance between them and k the constant . So:
Using that value on (1) and solving for a
Answer:
(a) T = 0.015 N
(b) M = 1.53 x 10⁻³ kg = 1.53 g
Explanation:
(a) T = 0.015 N
First, we will find the speed of waves:
where,
v = speed of wave = ?
f = frequency = 120 Hz
λ = wavelength = 6 cm = 0.06 m
Therefore,
v = (120 Hz)(0.06 m)
v = 7.2 m/s
Now, we will find the linear mass density of the coil:
where,
μ = linear mass density = ?
m = mass = 1.45 g = 1.45 x 10⁻³ kg
l = length = 5 m
Thereforre,
Now, for the tension we use the formula:
<u>T = 0.015 N</u>
<u></u>
(b)
The mass to be hung is:
<u>M = 1.53 x 10⁻³ kg = 1.53 g</u>