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.

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:

Where m is the remaining amount and n is th number of half lives in the time given.
Using this formula we can calculate:

Doing this calculation we get:

As we can see a very small value remains.
Answer:

Explanation:
When top block is just or about to slide on the lower block then we can say that the frictional force on it will be maximum static friction
So we will have






now for the Net force on two blocks to move together



Research has shown that the electrons orbit the nucleus in circular motions as shown on the classic Bohr model. FALSE
The car is the heaviest object there and mass is proportional to force, meaning the heavier it is the bigger the force should be in order to move it.
Answer:
<h3><u>If the mass of both of the objects is doubled, then the force of gravity between them is quadrupled; and so on. Since gravitational force is inversely proportional to the square of the separation distance between the two interacting objects, more separation distance will result in weaker gravitational forces.</u></h3>