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DanielleElmas [232]
3 years ago
5

A substance has a half-life of 10,000 years and an initial mass of 1,000 grams. How many years will pass before only 250 grams o

f the substance's parent material is left?
A. 20,000
B.25,000
C. 30,000
D.40,000
Physics
2 answers:
solmaris [256]3 years ago
6 0
<h3>♫ - - - - - - - - - - - - - - - ~Hello There!~ - - - - - - - - - - - - - - - ♫</h3>

➷ After 10,000 years the mass will be:

1,000 / 2 = 500

After 20,000 years the mass will be:

500/2 = 250

As you can see, the correct answer would be A. 20,000 years

<h3><u>✽</u></h3>

➶ Hope This Helps You!

➶ Good Luck (:

➶ Have A Great Day ^-^

↬ ʜᴀɴɴᴀʜ ♡

Pavel [41]3 years ago
4 0

Answer:

A). t = 20,000 years

Explanation:

Half life is the total time after which the substance will decay and remains only half of the initial amount

So here we will say that

initial amount is 1000 gram

Now after one half life only half of the amount will remain

so it is

m_1 = 1000/2 = 500 gram

now again after another half life it will remain half of the initial amount

so it is

m_2 = 500/2 = 250 gram

so it took two half lives

t = 10,000 + 10,000

t = 20,000 years

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If an object is thrown in an upward direction from the top of a building 160 ft. High at an initial speed of 21.82 mi/h what is
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First, we are going to convert 21.82 mi/h to ft/s:
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We know for our problem that the object is thrown in upward direction, so its velocity at its maximum height (before falling again) will be zero; therefore: V_{f}=0. We also know that it initial speed is 31.21 ft/s, so V_{i}=31.21. Lets replace those values in our formula to find t:
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Now we can add the height of the building and the maximum height of the object:
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d=V_{i}t+ \frac{1}{2} gt^2
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V_{f}=110.25 ft/s

We can conclude that the speed of the object when it hits the ground is 110.25 ft/s


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