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Mashutka [201]
3 years ago
15

If you have 10.0 g of a substance that decays with a half-life of 14 days, then how much will you have after 42 days?

Physics
1 answer:
Nat2105 [25]3 years ago
6 0
The formula for the mass that remains:
m=m_0 \times (\frac{1}{2})^\frac{t}{T}
m₀ - the initial mass, t - time, T - the half-life

m_0=10 \ g \\
T=14 \ d \\
t=42 \ d \\ \\
m=10 \times (\frac{1}{2})^\frac{42}{14}=10 \times (\frac{1}{2})^3=10 \times \frac{1}{8}=10 \times 0.125=1.25

The answer is c. 1.25 g.
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kiruha [24]

Answer:

15.19°, 31.61°, 51.84°

Explanation:

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We know that the expression for wavelenght is,

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Substituting,

\lambda = \frac{344}{1250}

\lambda = 0.2752m

Once we have the wavelenght we can find the angle by the equation of the single slit difraction,

sin\theta = \frac{m \lambda}{W}

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W is the width

m is the integer

\lambda the wavelenght

Re-arrange the expression,

\theta = sin^{-1} \frac{m\lambda}{W}

For m=1,

\theta = sin^{-1} \frac{1 (0.2752)}{1.05}= 15.19\°

For m=2,

\theta = sin^{-1} \frac{2 (0.2752)}{1.05}= 31.61\°

For m=3,

\theta = sin^{-1} \frac{3 (0.2752)}{1.05}= 51.84\°

<em>The angle of diffraction is directly proportional to the size of the wavelength.</em>

5 0
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Which type of interference occurs when two waves exactly cancel out? NEED AN ANSWER ASAP
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4 0
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A fuel pump sends gasoline from a car's fuel tank to the engine at a rate of 5.64 10-2 kg/s. the density of the gasoline is 735
Irina18 [472]
Given:
Gasoline pumping rate, R = 5.64 x 10⁻² kg/s
Density of gasoline, D = 735 kg/m³
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Let v =  speed of pumping the gasoline, m/s
Then the mass flow rate is 
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The gasoline pumping rate is given as 5.64 x 10⁻² kg/s, therefore
0.027166v = 0.0564
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Answer:  2.076 m/s
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7 0
3 years ago
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To pull an old stump out of the ground, you and a friend tie two ropes to the stump. You pull on it with a force of 500 N to the
zhannawk [14.2K]

Answer:

C. less than 950 N.

Explanation:

Given that

Force in north direction F₁ = 500 N

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Lets take resultant force R

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θ = 45°

The resultant force R

R=\sqrt{F_1^2+F_2^2+2F_1F_2cos\theta}

R=\sqrt{500^2+450^2+2\times 450\times 500\times cos\theta}

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Therefore resultant force is less than 950 N.

C. less than 950 N

Note- When these two force will act in the same direction then the resultant force will be 950 N.

8 0
3 years ago
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