involves removing the top layer of earth, mining the coal, and then replacing the earth back on the surface.

If the half-life of tritium (hydrogen-3) is 12.3 years, how much of

tatyana61 [14]

Answer:

0.0000076 grams

Explanation:

We're given the half life of Tritium to be 12.3 years. In order to find out the amount of substabce remaining:

Let's first find how many 'half lives' are in 250 years.

$n = \frac{250}{12.3} = 20.325$

Now what is half life? It means the time taken for a given quantity of an element to lose half it's mass.

So in 12.3 years we can find that The amount of 250 g of Tritium will be 250/2 = 125 g. In 24.6 years we'll have 125/2 = 62.5 g

So now we can devise a formula:

$m = \frac{original \: amount}{ {2}^{n} }$

Where m is the remaining amount and n is th number of half lives in the time given.

Using this formula we can calculate:

$m = \frac{10}{ {2}^{20.325} }$

Doing this calculation we get:

$m = 0.0000076 \: g$

As we can see a very small value remains.

4 0

2 years ago

A house is lifted from its foundations onto a truck for relocation. The house is pulled upward by a net force of 2850 N. This fo

Gwar [14]

Answer:

m = 95000 kg

Explanation:

Given that,

Net force acting on the house, F = 2850 N

Initial speed, u = 0

Final speed, v = 15 cm/s = 0.15 m/s

We need to find the mass of the house. Let the mass be m. We know that the net force is given by :

F = ma

Where

a is the acceleration of the house.

So,

$F=m\dfrac{v-u}{t}\\\\m=\dfrac{Ft}{(v-u)}\\\\m=\dfrac{2850\times 5}{(0.15-0)}\\\\m=95000\ kg$

So, the mass of the house is equal to 95000 kg.

3 0

2 years ago

Tsunami waves are caused by earthquakes in the ocean floor. As the waves approach the shore, they usually grow in height. When t

aksik [14]

Answer:

LETTER A. AMPLITUDE

:)

3 0

3 years ago

Read 2 more answers

A 450-N rightward force is used to drag a large box across the floor with a constant velocity of 1.2 m/s. The coefficient of fri

Nikolay [14]

Answer:

the mass of the box is 51.98 kg.

Explanation:

Given;

applied horizontal force, F = 450 N

coefficient of friction, μ = 0.795

constant velocity, v = 1.2 m/s

At constant velocity, the acceleration of the object is zero and the net force will be zero.

$F_{Net} = F - F_k\\\\0 = F - F_k\\\\F_k = F\\\\\mu \ N = F\\\\\mu (mg) = F\\\\m = \frac{F}{\mu g} \\\\m = \frac{405}{0.795 \ \times \ 9.8} \\\\m = 51.98 \ kg$

Therefore, the mass of the box is 51.98 kg.

8 0

2 years ago

If planet i is 30.3 million miles farther from the sun than planet ii, then planet iii is 24.6 million miles farther from the s

kkurt [141]

Since the total distance for all three of the planets is 196.2 million miles, you would add planet i and planet iii, then subtract that number from 196.2

planet i and planet iii equaled 54.9 million miles, that subtracted from 196.2 equals 141.3

So your answer is 141.3 million miles

3 0

2 years ago