## Mass Vs. Weight - the Conundrum.

**Mass**is the stuff Matter is made of

**Weight**is the gravitational pull on Matter.

If you stand on a "Weighing" scale, the number that shows up - say 70 pounds (31.1 kilograms)- is your weight right? That's what everyone says and that is is what has been said forever!!

Turns out, the

**70 pounds is your Mass**and not your weight. Go figure!!

## Weight is the gravitational pull on Mass.

It is the

**Force**with which Earth pulls an object toward itself.*Check out this interesting video on the*manner.

**Khanacademy website**that explains this difference in a very simple and easy to understand**https://www.khanacademy.org/science/physics/newton-gravitation/gravity-newtonian/v/mass-and-weight-clarification**

Remember Newton's 2nd Law of Motion that states Force depends on Mass and Acceleration ? F = m * a

Earth's gravitational acceleration is 9.8 m/s2 or 32.2 ft/s2. It has its own notation and is written as

The Force with which Earth pulls objects toward itself is written as

Doing this math in SI Units,

If your mass = 31.1 kg (70 pounds) and g = 9.8 m/s2

Force = 31.1 kg * 9.8 m/s2. (9.8 can be approximated to 10)

So, Force = 311 kg m/s2 or 311 Newton.

Your

Earth's gravitational acceleration is 9.8 m/s2 or 32.2 ft/s2. It has its own notation and is written as

**"g".**The Force with which Earth pulls objects toward itself is written as

**F = m * g,**where**m = mass**of the object and**g = 9.8 m/s2**or**32.2 ft/s2.****This F = mass x 9.8 m/s2 is our weight on Earth**Doing this math in SI Units,

If your mass = 31.1 kg (70 pounds) and g = 9.8 m/s2

Force = 31.1 kg * 9.8 m/s2. (9.8 can be approximated to 10)

So, Force = 311 kg m/s2 or 311 Newton.

Your

**weight**on Earth is 311 Newton. Newton is a unit of measure for Force.**At 70 pounds, you exert a Force of 311 Newton on Earth. A Force greater than 311 Newton will be required to push or pull you.**## On the Moon?

Moon's gravitational force is 6 times lesser than that on Earth. By that definition, your

Weight on Moon = 311 Newton/6 = about 51 newtons.

**Weight**on the Moon will beWeight on Moon = 311 Newton/6 = about 51 newtons.

If this was too complicated to understand, a simple explanation is, the number you see in your weighing scale is actually your Mass. Your Mass will stay constant regardless of where you are on Earth or in Space.

Your weight will vary depending on whether you are on Earth, on the Moon or elsewhere in Space.

Q) Can you guess why ?

Your weight will vary depending on whether you are on Earth, on the Moon or elsewhere in Space.

**Trivia:**Your weight will be slightly lower in the Artics or Anatartic than if you were closer to the equator (e.g. Hawaii)Q) Can you guess why ?

*After spending a good amount of time on Gravitational force, lets move on to Frictional Force*