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3 years ago

the half-life of carbon-14 is 5,730 years. After 11,460 year, how much of original carbon-14 remains?

Physics

1 answer:

Inessa [10]3 years ago

6 0

Via the half-life equation:

$A_{final}=A_{initial}(\frac{1}{2})^{\frac{t}{h}}$

Where the time elapse is 11,460 year and the half-life is 5,730 years.

$A_{final}=A_{initial}(\frac{1}{2})^\frac{11460}{5730} \\\\A_{final}=A_{initial}\frac{1}{4} \\\\A_{final}=\frac{1}{4}A_{initial}$

Therefore after 11,460 years the amount of carbon-14 is one fourth (1/4) of the original amount.

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PLEASE HELP ME WITH THIS PROBLEM

valentinak56 [21]

1) The mass of the continent is $2.13\cdot 10^{21} kg$

2) The kinetic energy of the continent is 274.8 J

3) The speed of the jogger must be 2.76 m/s

Explanation:

The continent is a slab of side 5900 km (so the surface is 5900 x 5900, assuming it is a square) and depth 26 km, therefore its volume is:

$V=(36)(4600)^2=7.62\cdot 10^8 km^3 = 7.62\cdot 10^{17} m^3$

The mass of the continent is given by

$m=\rho V$

where:

$\rho = 2790 kg/m^3$ is its density

$V=7.62\cdot 10^{17} m^3$ is its volume

Substituting, we find the mass:

$m=(2790)(7.62\cdot 10^{17})=2.13\cdot 10^{21} kg$

To find the kinetic energy, we need to convert the speed of the continent into m/s first.

The speed is

v = 1.6 cm/year

And we have:

1.6 cm = 0.016 m

$1 year = (365)(24)(60)(60)=3.15\cdot 10^7 s$

So, the speed is

$v=\frac{0.016 m}{3.15 \cdot 10^7 s}=5.08\cdot 10^{-10}m/s$

Now we can find the kinetic energy of the continent, which is given by

$K=\frac{1}{2}mv^2$

where

$m=2.13\cdot 10^{21} kg$ is the mass

$v=5.08\cdot 10^{-10}m/s$ is the speed

Substituting,

$K=\frac{1}{2}(2.13\cdot 10^{21})(5.08\cdot 10^{-10})^2=274.8 J$

The jogger in this part has the same kinetic energy of the continent, so

K = 274.8 J

And its mass is

m = 72 kg

We can write his kinetic energy as

$K=\frac{1}{2}mv^2$

where

v is the speed of the man

And solving the equation for v, we find his speed:

$v=\sqrt{\frac{2K}{m}}=\sqrt{\frac{2(274.8)}{72}}=2.76 m/s$

Learn more about kinetic energy:

brainly.com/question/6536722

#LearnwithBrainly

3 0

3 years ago

Any example of acceleration related to human body??? <br> answer quickly plz :)

Hitman42 [59]

Answer:

Acceleration stress, physiological changes that occur in the human body in motion as a result of rapid increase of speed. ... A force of 3 g, for example, is equivalent to an acceleration three times that of a body falling near Earth.

4 0

2 years ago

Rock composed of many thin layers. This image appears in an Earth science magazine with this caption: "A non-foliated rock found

blondinia [14]

Answer:

its B

Explanation:

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This device combines multiple circuits at one end of a connection into a single complex circuit on a single wire. The signal is

lilavasa [31]

Answer:

Multiplexer

Explanation:

-In electronics, a multiplexer, also known as a data, is a device that selects between several analog or digital input signals and forwards it to a single output line.

-This device combines multiple circuits at one end of a connection into a single complex circuit on a single wire.

-The selected signals is then transmitted at a higher speed.

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3 years ago

How is thermal energy naturally transferred between objects?

Sladkaya [172]

The second law of thermodynamics establishes restrictions on the flow of thermal energy between two bodies. This law states that the energy does not flow spontaneously from a low temperature object T1, to another object that is at a high temperature T2.

For example. Suppose you place your cell phone on the table. Your phone is at a temperature of 40 ° C and the table is at 19 ° C. Then, it is impossible for the table to spontaneously transfer its thermal energy to the telephone, and so that the table gets colder and the telephone warmer.

Finally we can say that the correct option is B: From the hotter object to the cooler object

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