mass and weight. sorry about the wait

Mass and Weight

Sorry about the wait.

Is she calling

me fat?!!

Some people just don’t understand the concept of weight.

Eg Which weighs more, a tonne of rocks or a tonne of soft duck feathers?

Some people just don’t understand the concept of weight.

Eg Which weighs more, 1 tonne of rocks or 1 tonne of soft duck feathers?

They both have a mass of 1 tonne.

Do mass and weight have the same meaning?

Will 1 tonne of rocks always have the same weight?

In space you can be weightless, will your mass have changed?

Do mass and weight have the same meaning? NO

Will 1 tonne of rocks always have the same weight?



Will 1 tonne of rocks always have the same weight? NO



Will 1 tonne of rocks always have the same weight? NO

In space you can be weightless, will your mass have changed? NO


Mass refers to the amount of ‘stuff’ in an object. This is determined by the atoms in the object. This DOES NOT change.


Weight is a force that a mass exerts. eg Masses are pulled towards the centre of the Earth by gravity. This attraction causes a mass to push against the surface of the Earth. This push is called its weight.


To better understand gravity complete the worksheets:

‘A Brief History of Gravity’ and

‘Warp Factor’.


The force of gravity causes objects to accelerate towards Earth with an acceleration of 9.8metres per second per second ie it gets faster by 9.8metres per second every second ie 9.8ms-2


This acceleration due to gravity is given the symbol g.

Weight force = mass x g

ie wt = mg


Eg What is my weight on Earth, if my mass is 80kg?!

m = 80kg

g = 9.8ms-2



m = 80kg wt = mg

g = 9.8ms-2



m = 80kg wt = mg

g = 9.8ms-2 wt = 80 x 9.8



m = 80kg wt = mg

g = 9.8ms-2 wt = 80 x 9.8

= 784N


The size of a weight force is not constant, it can change for a mass.

mass and weight. sorry about the wait

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