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3 years ago

A sample contains 10 g of a radioactive isotope. How much radioactive isotope will remain in the sample after 2 half-lives?

Physics

2 answers:

xxMikexx [17]3 years ago

5 0

The answer c - Half life how to figure, you first divide it by half then divide than number by half

k0ka [10]3 years ago

3 0

Answer:

c) 2.5 g

Explanation:

half-life is the time it takes the radioactive isotope to decay to half of the intial sample.

so if the isotope decays to 2 half-lives, it will decay half the intial sample twice.

in the first half-life, the sample will decay from 10 g to 5 g. during the second half-life, the isotope will decay from 5 g to 2.5 g.

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Buffalo, New York, and Raleigh, NC, lie approximately on the same meridian. Buffalo has a latitude of 42.9° N, and Raleigh has a

yulyashka [42]

Answer:

Distance will be $=3960\times 0.12385=490.468miles$

Explanation:

We have given that Buffalo has a latitude of 42.9°N

And Raleigh has a latitude of 35.8°N

Radius of the earth = 3960 miles

We have to calculate the distance between given two cities

Difference in their latitudes = $42.9-35.8=7.1^{\circ}$

Now changing the angle in radian = $7.1\times\frac{\pi }{180}=0.12385radian$

So distance will be $=3960\times 0.12385=490.468miles$

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2 years ago

Solve the inequality 2(n+3) – 4<6. Then graph<br> the solution.

Aloiza [94]

The solution is 22 2(n+3)-4&6

6 0

2 years ago

Water, H2O ,and methane ,CH4, are both covalent substances . why is water a liquid at room temperature while methane is a gas ?

stiv31 [10]

I think the answer is b

7 0

2 years ago

Read 2 more answers

A roller coaster car may be approximated by a block of mass m. Thecar, which starts from rest, is released at a height h above t

elena55 [62]

Answer:

The first part can be solved via conservation of energy.

$mgh = mg2R + K\\K = mg(h-2R)$

For the second part,

the free body diagram of the car should be as follows:

- weight in the downwards direction

- normal force of the track to the car in the downwards direction

The total force should be equal to the centripetal force by Newton's Second Law.

$F = ma = \frac{mv^2}{R}\\mg + N = \frac{mv^2}{R}$

where $N = 0$ because we are looking for the case where the car loses contact.

$mg = \frac{mv^2}{R}\\v^2 = gR\\v = \sqrt{gR}$

Now we know the minimum velocity that the car should have. Using the energy conservation found in the first part, we can calculate the minimum height.

$mgh = mg2R + \frac{1}{2}mv^2\\mgh = mg2R + \frac{1}{2}m(gR)\\gh = g2R + \frac{1}{2}gR\\h = 2R + \frac{R}{2}\\h = \frac{5R}{2}$

Explanation:

The point that might confuse you in this question is the direction of the normal force at the top of the loop.

We usually use the normal force opposite to the weight. However, normal force is the force that the road exerts on us. Imagine that the car goes through the loop very very fast. Its tires will feel a great amount of normal force, if its velocity is quite high. By the same logic, if its velocity is too low, it might not feel a normal force at all, which means losing contact with the track.

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2 years ago

Highlight two factors which shows that heat from the sun does reach the earth's surface by convection.

MAXImum [283]

radiation

when the suns radiation fall on the earth and its objects they receive heat energy and hence get heated. Thus the suns heat reaches the earth by. the process of radiation

3 0

2 years ago