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3 years ago

I Need help with this problem i don’t know what to do

Physics

1 answer:

Mazyrski [523]3 years ago

8 0

Answer:

The density of the sample is 36 g/cm³

Explanation:

m= 972g

l=3cm

V = l³ = 3³ = 27 cm³

density = mass/volume

= 972/27

= 36 g/cm³

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The tension in the rope securing the upper pulley and the force that must be applied to keep the system in equilibrium

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Explanation:

In a frictionless system with no acceleration, the tension in the rope must be F along its entire length

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3 years ago

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If the sun is scaled down to 9.5 inches in diameter, the earth would be about _____ inches in diameter

vovangra [49]

Answer: 0.087 inches

Explanation:

This problem can be solved applying the <u>Rule of three</u>, which is a mathematical rule to find out an amount that is with another quantity given in the same relation as other two also known.

In this sense, the actual diameter of the Sun is 1,391,020 km and the actual diameter of the Earth is 12,742 km.

Now, applying the <u>Rule of three:</u>

<u />

Sun 1,391,020 km ------ 9.5 inches

Earth 12,742 km --------- ? inches

$? inches=\frac{(12,742 km)(9.5 inches)}{1,391,020 km}$

$? inches=0.087 inches$

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3 years ago

A 50.0 mg sample of an unknown radioactive substance was placed in storage and its mass measured periodically. After 19.7 days,

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<h2>Answer: 4.928 days </h2><h2 />

Explanation:

This problem can be solved using the <u>Radioactive Half Life Formula: </u>

<u></u>

$A=A_{o}.2^{\frac{-t}{h}}$ (1)

Where:

$A=3.13mg$ is the final amount of the material

$A_{o}=50mg$ is the initial amount of the material

$t=19.7days$ is the time elapsed

$h$ is the half life of the material (the quantity we are asked to find)

Knowing this, let's substitute the values and find $h$ from (1):

$3.13mg=(50mg)2^{\frac{-19.7days}{h}}$ (2)

$\frac{3.13mg}{50mg}=2^{\frac{-19.7days}{h}}$ (3)

Applying natural logarithm in both sides:

$ln(\frac{3.13mg}{50mg})=ln(2^{\frac{-19.7days}{h}})$ (4)

$-2.77=-\frac{19.7days}{h}ln(2)$ (5)

Clearing $h$ :

$h=\frac{-19.7days}{-2.77}(0.693)$ (6)

Finally:

$h=4.928days$

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