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AfilCa [17]
2 years ago
5

A student has an 80 g sample of a radioactive material that has a half-life of 20 seconds. How much material will he have left a

fter 60 seconds?
A.
10 g

B.
20 g

C.
40 g

D.
5 g
Physics
1 answer:
Juliette [100K]2 years ago
7 0
The answer is C 40 g
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The spraying of pesticides can be carefully planned, but accidents, weather conditions that could not be foreseen, and pilot err
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Answer:

B) weather conditions that cannot be foreseen, and pilot errors often cause much larger deposits of spray than

Explanation:

Option B obeys the principle of parallelism because the two phrases, " can be carefully planned" and "cannot be foreseen" follow the same grammatical structure. Option A does not obey parallelism because " can be carefully planned" and "could not be foreseen" do not follow the same grammatical structure.

The phrase " they had anticipated" in the other options apart from B do not have a matching subject. Pilot errors is the subject in this sentence and it is not expected to anticipate anything, only the pilots can.

Moreover, "that cannot be foreseen" is more parallel to "can be carefully planned" that "unforeseeable" or "foreseeable" used in the other options

6 0
3 years ago
Multiplying or dividing vectors by scalars results in a. vectors. b. scalars. c. vectors if multiplied or scalars if divided. d.
klemol [59]
Let A = i+j+k be a vector and B = 3 be any scalar, 
Multiplying A and B, 
AB = (i+j+k)3 = 3i+3j+3k 

Which is a new vector whose direction is same as the old but it's 3 times greater in length  than the old vector(i+j+k).

Now, dividing A and B,
A/B = (i+j+k)/3 = \frac{1}{3}i +  \frac{1}{3}j + \frac{1}{3}k

Which is again a new vector whose direction is same as the old but now it's 1/3 times small in length than the old vector. 

Direction is same because we multiplied by positive scalar. If we multiply A by suppose -1, -4, -1000000 or any negative number, it's direction will reverse. 

Thus, if we multiply a vector with scalar, it's length increases. If we divide, it shrinks. 
8 0
3 years ago
Read 2 more answers
Compare and contrast electric conductors and electric insulators. Give an example of each.
8090 [49]

Answer:

conductor:-

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Example:-All the metals, water, etc.

Insulator:-

A substance that does not allows heat to pass through them is known as an insulator.

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Explanation:

4 0
2 years ago
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diamong [38]

Answer:

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Explanation:

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= 0.5 * 95 * Squared of (40)

= 7.6*10^4J

5 0
3 years ago
Does mass affect the final velocity of an object if the object begins with a high initial velocity?
victus00 [196]
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