It's difficult to measure that because it's hard to make sure it is only a uniform layer of gas in whatever you're measuring it in
PEg = Mass x Height x Gravity. So it doesn't matter how much PEg she started with, since you're finding how much it changed when she walked down 2.5 meters of stairs. So by plugging into the equation, you'll find how much potential energy was lost by walking down. (I'll leave it up to you since idk if you use 10 or 9.8 as gravity)
Answer:B
Explanation:
Option A:
In the nuclear reactions,neutron can be split into proton an electron.
In this case,the number of protons are increasing,increasing the atomic number.
Hence,the atomic number is not conserved.
Option B:
In any reaction the sum of number of neutrons and number of protons remain constant before and after the reaction.
Option C:
The mass number may change for the atoms.For example 
emission reduces the atomic number by 
Option D:
In the nuclear reactions,neutron can be split into proton an electron.
So,they number of neutrons may change.
Answer:
What wave is a sound wave?
For a sound wave traveling through air, the vibrations of the particles are best described as longitudinal. Longitudinal waves are waves in which the motion of the individual particles of the medium is in a direction that is parallel to the direction of energy transport.
Explanation:
If you're careful, you ought to be able to observe ANY of these properties
without any effect on the substance:
Absorption, albedo, angular momentum, area, color, concentration,
density, elasticity, electric charge, electrical conductivity, flow rate,
electrical impedance, electric potential, fluidity, length, location, mass,
luminance, luminescence, luster, magnetic field, momentum, opacity,
permeability, permittivity, plasticity, pressure, radiance, solubility, spin,
specific heat, resistivity, reflectivity, refractive index, temperature,
thermal conductivity, velocity, viscosity, or volume.
