Mass [2]
Difference between Mass and Weight
Mass is an amount that the object originally has.
Mass is not newly generated. It doesn't disappear.
(Strictly, mass is converted into energy, and disregard it here because it is non-daily. )
Mass doesn't change wherever it is because mass is an original amount of the object.
Mass is always constant without any relation to the temperature, pressure, and the place.
Of course, mass is constant without any relation to the presence of the action of gravitation.
Gravitation works between mass and mass. This is called universal gravitation.
Especially, the gravitation caused between the earth (Or, other heavenly bodies) and objects is called gravity.
The magnitude of gravity is called weight. To tell the truth, weight is a kind of force.
When force is added to the object, it accelerates.
This is a second law of motion.
When the vehicle has accelerated, the passenger feels force.
In a word, force and the acceleration are proportional.
In the second law of motion, force is expressed by the product of mass and the acceleration.
Gravity is force.
Therefore, gravity is expressed by the product of mass and the acceleration as well as other force.
Gravity acts on the falling object.
Therefore, the velocity of the falling object quickens fast.
The acceleration of the dropping object is called gravitational acceleration.
| Weight is a product of mass and gravitational acceleration g. |
The acceleration when the object falls isg.
It is a difference of mass and weight as follows.
| mass | weight |
| kg | kg*m/s2 |
| It doesn't change because it is an original amount of the object. | Product of mass and gravitational acceleration. magnitude of force to which the earth pulls object. Weight changes, too, if force is changed. |
1000 times the [kg] are often used though the unit of mass is [g].
It is because a basic unit of SI unit is [kg].
Mass is a concept not understood easily. There are a lot of people who mistake weight for mass, too.
It writes again though it becomes a repetition.
Mass is invariable even if going to where.
Weight is gravity caused by universal gravitation.
Gravity is force, and the magnitudee is a product of mass and gravitational acceleration.
Here, I want to take care occasionally.
It is "Mass" that we say usually, "Weight".
"Mass" is correct as physics. However, it is said, "Weight" as a custom.
It is expressed in daily life, "Weight is ** kg".
The unit of mass is kg, the unit of weight is kg m/s2
Contradiction is included in the expression "Weight is ** kg".
It should be said, "Mass is ** kg" in the viewpoint of physics.
However, it was expressed as a custom of the language, "Weight is ** kg".
This is one of the factors that mass is confused with weight.