Mass is a body of matter of indefinite shape and considerable size. Density is the degree to which something is filled. Check this website for more a better understanding : <span>www.answers.com/Q/What_is_the_relationship_between_density_and_volume</span>
The answer is A. Newton's third law of motion states that for every action, there is an equal and opposite reaction. A rocket exerts a large force on the gas that is in the rocket chamber (action). The gas thus exerts a large reaction force forward on the rocket (reaction). The large reaction force is called thrust.
Answer:
When the magnetic field is tilted so it is no longer perpendicular to the page.
When the magnetic field gets stronger.
When the size of the loop decreases.
Explanation:
According to the Faraday-Lenz law, the change of the magnetic flux over time causes an induced current, this flux is given by:

Therefore, there will be a variable magnetic flux, when the magnitude of the magnetic field (B) changes over time, when the area of the loop (S) changes over time and / or when the angle (
) between the field and the surface vector changes over time.
Answer:
RE of Hydrogen = 6.47 x RE of Krypton
Explanation:
Actually the correct formula for comparing rate of effusion (RE) of two gases is:
RE of Gas A
------------------- = √ ( Molar mass of B / Molar mass of A)
RE of Gas B
You can designate which of the two gases you have (hydrogen and krypton) will be your gas A and gas B. So for this particular problem, let us make hydrogen as gas A and Krypton as gas B. So the equation becomes:
RE of Hydrogen
------------------------- = √ (Molar mass of Krypton / Molar mass of Hydrogen)
RE of Krypton
Get the molar masses of Hydrogen and Krypton in the periodi table:
RE of Hydrogen
------------------------- = √ (83.798 g/mol / 2 g/mol)
RE of Krypton
RE of Hydrogen
------------------------- = 6.47 ====> this can also be written as:
RE of Krypton
RE of Hydrogen = 6.47 x RE of Krypton
It means that the rate of effusion of Hydrogen gas will be 6.47 faster than the rate of effusion of Krypton gas. With the type of question you have, it doesn't matter which gases goes on your numerator and denominator. What's important is that you show the rate of effusion of a gas with respect to the other. But if that's concerns you the most, then take the gas which was stated first as your gas A and the latter as your gas B unless the problem tells you which one will be on top and which is in the bottom.