Answer:
a) m=20000Kg
b) v=0.214m/s
Explanation:
We will separate the problem in 3 parts, part A when there were no coals on the car, part B when there is 1 coal on the car and part C when there are 2 coals on the car. Inertia is the mass in this case.
For each part, and since the coals are thrown vertically, the horizontal linear momentum p=mv must be conserved, that is,
, were each velocity refers to the one of the car (with the eventual coals on it) for each part, and each mass the mass of the car (with the eventual coals on it) also for each part. We will write the mass of the hopper car as
, and the mass of the first and second coals as
and
respectively
We start with the transition between parts A and B, so we have:

Which means

And since we want the mass of the first coal thrown (
) we do:



Substituting values we obtain

For the transition between parts B and C, we can write:

Which means

Since we want the new final speed of the car (
) we do:

Substituting values we obtain

That nutritional information is usually not posted up on the wall,
but by federal law, it's available on request, to any customer, at
any fast-food place.
All she has to do is ask to see the manager, and then ask the
manager for the nutritional information booklet.
She'll get a nice printed booklet that tells the salt content in the
fries, AND the amount of many other substances in ALL the items
sold at that place.
It's the law. Don't be bashful.
Answer:

Explanation:
The time the stone takes to fall can be calculated considering only the vertical component with the formula:

Taking the inital height as 0m and downward direction positive, since it departs from (vertical) rest we have:

Which gives us a time:

Horizontally, on that time the stone travelled a distance x=10m, which means its horizontal speed was:

Since <u>this speed is the tangential velocity</u> while whirling, the centripetal acceleration of the stone was:

We can't see the graph.
But is has to show that wavelength and frequency are inversely
proportional. In other words, their product is constant.
That's because their product is the speed of the wave.
If the graph doesn't show that, then the graph is wrong.
The correct answers are:
B) Producers supply enough goods for consumers;
D) Supply equals demand;
In the economics, the equilibrium state basically means that the supply in the market is well balanced with the demand on the market, thus leading to an ideal economic state within the economy. The equilibrium will essentially mean that the supply is equal to the demand, thus there will be maximum efficiency. Also, since the producers are managing to supply just the right amount of goods to the consumers, everyone will benefit, with the consumers always have what they want, and the producers always have all of their products sold.