Answer:
0.75 g/cm^3
Explanation:
The formula for density:

Where m is the mass and V is the volume.
So, we can substitute values for m and V:

Therefore, the density is 0.75 g/cm^3 (watch the units!)
Answer:
<em>Yes, they are moving in opposite direction one to the other.</em>
Explanation:
Velocity is a vector quantity, which means that it has both magnitude and direction. The magnitude shows the size of the velocity, and the direction shows which way it is moving in reference to a chosen reference direction. If the red box is assigned a positive velocity, and the blue box is assigned a negative velocity, as indicated in the question, then it means that the red box, and the blue box, both move in opposite direction to the other.
The De Broglie wavelength of the electron is

And we can use De Broglie's relationship to find its momentum:

Given

, with m being the electron mass and v its velocity, we can find the electron's velocity:

This velocity is quite small compared to the speed of light, so the electron is non-relativistic and we can find its kinetic energy by using the non-relativistic formula:
The first one is dependent variable
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Answer:
When iron rusts - in the presence of moisture and oxygen - iron-oxide is formed. Iron oxide is nothing but a compound of iron and oxygen. There is an increase in the mass of the iron equal to the mass of oxygen that has gone into forming the rust.
<em>hope it helps:)</em>