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Veritasium video on falling objects - 1


Weight is the gravitational force that the Earth exerts on any object. The weight of an objects gives you an indication of how strongly the Earth attracts that body towards its centre. Weight is calculated as follows:

Weight = m g

where m = mass of the object (in kg)

and g = the acceleration due to gravity ( 9,8 m · s - 2 )

For example, what is Sarah's weight if her mass is 50 kg . Sarah's weight is calculated according to:

Weight = m g = ( 50 kg ) ( 9 , 8 m · s - 2 ) = 490 kg · m · s - 2 = 490 N

Weight is sometimes abbreviated as F g which refers to the force of gravity. Do not use the abbreviation W for weight as it refers to `Work'.

Now, we have said that the value of g is approximately 9,8 m · s - 2 on the surface of the Earth. The actual value varies slightly over the surface of the Earth. Each planet in our Solar System has its own value for g . These values are listed as multiples of g on Earth in [link]

A list of the gravitational accelerations at the surfaces of each of the planets in our solar system. Values are listed as multiples of g on Earth. Note : The "surface" is taken to mean the cloud tops of the gas giants (Jupiter, Saturn, Uranus and Neptune).
Planet Gravitational Acceleration (multiples of g on Earth)
Mercury 0,376
Venus 0,903
Earth 1
Mars 0,38
Jupiter 2,34
Saturn 1,16
Uranus 1,15
Neptune 1,19
Pluto 0,066

Sarah's mass on Earth is 50 kg . What is her mass and weight on Mars?

  1. m (on Earth) = 50 kg

    m (on Mars) = ?

    Weight (on Mars) = ?

  2. Sarah's mass does not change because she is still made up of the same amount of matter. Her mass on Mars is therefore 50 kg .

  3. Sarah ' s weight = 50 × 0 , 38 × 9 , 8 = 186 , 2 N

Differences between mass and weight

Mass is measured in kilograms (kg) and is the amount of matter in an object. An object's mass does not change unless matter is added or removed from the object.

The differences between mass and weight can be summarised in the following table:

Mass Weight
1. is a measure of how much matter there is in an object. 1. is the force with which the Earth attracts an object.
2. is measured in kilograms. 2. is measured in newtons
3. is the same on any planet. 3. is different on different planets.
4. is a scalar. 4. is a vector.


  1. A bag of sugar has a mass of 1 kg . How much does it weigh:
    1. on Earth?
    2. on Jupiter?
    3. on Pluto?
  2. Neil Armstrong was the first man to walk on the surface of the Moon. The gravitational acceleration on the Moon is 1 6 of the gravitational acceleration on Earth, and there is negligible gravitational acceleration in outer space. If Neil's mass was 90 kg , what was his weight:
    1. on Earth?
    2. on the Moon?
    3. in outer space?
  3. A monkey has a mass of 15 kg on Earth. The monkey travels to Mars. What is his mass and weight on Mars?
  4. Determine your mass by using a bathroom scale and calculate your weight for each planet in the Solar System, using the values given in [link]

Acceleration due to gravity

Gravitational fields

A field is a region of space in which a mass experiences a force. Therefore, a gravitational field is a region of space in which a mass experiences a gravitational force.

Questions & Answers

How we are making nano material?
what is a peer
What is meant by 'nano scale'?
What is STMs full form?
scanning tunneling microscope
what is Nano technology ?
Bob Reply
write examples of Nano molecule?
The nanotechnology is as new science, to scale nanometric
nanotechnology is the study, desing, synthesis, manipulation and application of materials and functional systems through control of matter at nanoscale
Is there any normative that regulates the use of silver nanoparticles?
Damian Reply
what king of growth are you checking .?
What fields keep nano created devices from performing or assimulating ? Magnetic fields ? Are do they assimilate ?
Stoney Reply
why we need to study biomolecules, molecular biology in nanotechnology?
Adin Reply
yes I'm doing my masters in nanotechnology, we are being studying all these domains as well..
what school?
biomolecules are e building blocks of every organics and inorganic materials.
anyone know any internet site where one can find nanotechnology papers?
Damian Reply
sciencedirect big data base
Introduction about quantum dots in nanotechnology
Praveena Reply
what does nano mean?
Anassong Reply
nano basically means 10^(-9). nanometer is a unit to measure length.
do you think it's worthwhile in the long term to study the effects and possibilities of nanotechnology on viral treatment?
Damian Reply
absolutely yes
how to know photocatalytic properties of tio2 nanoparticles...what to do now
Akash Reply
it is a goid question and i want to know the answer as well
characteristics of micro business
for teaching engĺish at school how nano technology help us
How can I make nanorobot?
Do somebody tell me a best nano engineering book for beginners?
s. Reply
there is no specific books for beginners but there is book called principle of nanotechnology
how can I make nanorobot?
what is fullerene does it is used to make bukky balls
Devang Reply
are you nano engineer ?
fullerene is a bucky ball aka Carbon 60 molecule. It was name by the architect Fuller. He design the geodesic dome. it resembles a soccer ball.
what is the actual application of fullerenes nowadays?
That is a great question Damian. best way to answer that question is to Google it. there are hundreds of applications for buck minister fullerenes, from medical to aerospace. you can also find plenty of research papers that will give you great detail on the potential applications of fullerenes.
what is the Synthesis, properties,and applications of carbon nano chemistry
Abhijith Reply
Mostly, they use nano carbon for electronics and for materials to be strengthened.
is Bucky paper clear?
carbon nanotubes has various application in fuel cells membrane, current research on cancer drug,and in electronics MEMS and NEMS etc
how did you get the value of 2000N.What calculations are needed to arrive at it
Smarajit Reply
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Source:  OpenStax, Maths test. OpenStax CNX. Feb 09, 2011 Download for free at http://cnx.org/content/col11236/1.2
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