Answer:
It is called force of friction
Explanation:
The force of friction is a force that acts between two objects whose surfaces are in contact with each other.
Consider the typical case of an object sliding along a certain surface. There are two types of frictions:
- Static friction: this is the force of friction that acts when the object is not in motion yet. If you push the object forward with a force F, the object will not move immediately, but it will "oppose" to this motion with a force of static friction exactly equal to the push applied:
However, this force of static friction has a maximum value, which is given by
where
is the coefficient of static friction
N is the normal reaction exerted by the surface on the object
So, when 
becomes greater than 
, the static friction is no longer able to balance the push applied, and the object will start sliding forward.
- Kinetic friction: this is the force of friction that acts when the object is already in motion. Its magnitude is given by
where
is the coefficient of kinetic friction, and its value is generally smaller than . The direction of this force is also opposite to the direction of motion of the object.
The atomic number of an atom says how many protons it has. This number cant change, since the atomic number is what gives elements their identities (in the periodic table, at least).
The mass number, on the other hand, says how many protons AND neutrons the atom has (so, the sum of P+ and N0). So, electrons have nothing to do with this number.
Atoms are neutrally charged, which means there has to be an equal number of positive and negative particles. The negative particles of an atom are its electrons, and since our atom has 4 protons, it must also have 4 electrons.
If you measured all the energy related to motion and all the stored
energy in the particles of a substance, you would be measuring the thermal energy of the particles. If
there is movement of the particles, they are also releasing energy in the form
of heat.
Answer:
"How does the volume of a gas kept at constant pressure change as its temperature is increased?"
Explanation:
One possible question can be:
"How does the volume of a gas kept at constant pressure change as its temperature is increased?"
The answer to this question is contained in Charle's law, which states that for a gas at constant pressure, the volume of the gas is proportional to its absolute temperature:
Or also written as
By looking at this equation, we can find immediately the answer to our question: as the (absolute) temperature of the gas increases, the volume increases as well, by the same proportion.
By using the Plancks-Einstein equation, we can find the energy;
E = hf
where h is the plancks constant = 6.63 x 10⁻³⁴
f = frequency = 3.55 x 10¹⁷hz
E = (6.63 x 10⁻³⁴) x (3.55 x 10¹⁷)
E = 2.354 x 10⁻¹⁶J
