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ziro4ka [17]
3 years ago
5

(16 POINTS)

Physics
1 answer:
natta225 [31]3 years ago
7 0
Halflife is the time taken by a radioactive substance by half its original mass. In this case the half life of the substance is 3 hours. 
Therefore; New mass = Original mass × (1/2)^n where n is the number of half lives. In this case, the half life is 3 hours and therefore; the number of half lives in 6 hours will be two.
 = if the original mass is 100%
new mass = 100 × (1/2)^2
                 = 100 × 1/4 = 25%
The remaining mass will be 1/4 of the original mass, meaning  a fraction of 3/4 of the  initial mass will have decayed.
Thus; the answer is 3/4 












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How high does the water rise in the bell after enough time has passed for the air to reach thermal equilibrium
Minchanka [31]

The height risen by water in the bell after enough time has passed for the air to reach thermal equilibrium is 3.8 m.

<h3>Pressure and temperature at equilibrium </h3>

The relationship between pressure and temperature can be used to determine the height risen by the water.

\frac{P_1V_1}{T_1} = \frac{P_2V_2}{T_2}

where;

  • V₁ = AL
  • V₂ = A(L - y)
  • P₁ = Pa
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  • T₁ = 20⁰C = 293 K
  • T₂ = 10⁰ C = 283 k

\frac{PaAL}{T_1} = \frac{(P_a + \rho gh)A(L-y)}{T_2} \\\\\frac{PaL}{T_1} = \frac{(P_a + \rho gh)(L-y)}{T_2} \\\\L-y = \frac{PaLT_2}{T_1(P_a + \rho gh)} \\\\y = L (1 - \frac{PaT_2}{T_1(P_a + \rho gh)})\\\\y = 4.2(1 - \frac{101325 \times 283}{293(101325\  +\  1000 \times  9.8 \times  100)} )\\\\y = 3.8 \ m

Thus, the height risen by water in the bell after enough time has passed for the air to reach thermal equilibrium is 3.8 m.

The complete question is below:

A diving bell is a 4.2 m -tall cylinder closed at the upper end but open at the lower end. The temperature of the air in the bell is 20 °C. The bell is lowered into the ocean until its lower end is 100 m deep. The temperature at that depth is 10°C. How high does the water rise in the bell after enough time has passed for the air to reach thermal equilibrium?

Learn more about thermal equilibrium here: brainly.com/question/9459470

#SPJ4

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If a wave has a frequency of 74 Hz and a speed of 444 m/s, what is the wave's wavelength?
DaniilM [7]

Answer:

6 m

Explanation:

velocity = wavelength x frequency

444 m/s = wavelength x 74 Hz

444 m/s / 74 Hz = wavelength

wavelength = 6m

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Formulae for determining the magnitude of the load overcomed​
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A horizontal force of 400 N is exerted on a 2.0-kg ball as it rotates (at
frutty [35]

Answer:

the speed of the ball is 10 m/s

Explanation:

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magnitude of exerted force, F = 400 N

mass of the ball, m = 2 kg

radius of the circle, r = 0.5

The speed of the ball is calculated by applying centripetal force formula;

F = \frac{mv^2}{r} \\\\v^2 = \frac{Fr}{m}\\\\v = \sqrt{\frac{Fr}{m}}\\\\ v = \sqrt{\frac{400*0.5}{2}}\\\\v = 10 \ m/s

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6 0
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