MASS AND
Remember that…
 Weight and Mass are not the same!
 Mass will remain the same, weight will change because
gravitational force pulling on it will be different.
 Weight is a force measured in NEWTONS by a newton
meter or spring balance
 Mass is not a force. It is measured in kilograms with a mass
balance.
Why Scales Show
Kilograms or Pounds
Scales show Kilograms or Pounds because
that is what people understand best ...
… Scales should really show Newtons, but
that might confuse people!
 Grams (gr), Ounces (oz) and Pounds (lb) are also used in the
scales.
Practice …
 Solve the different exercises using pounds or ounces.
Now….. Weight….
WHAT IS WEIGHT?
Weight is the force of gravity on an object. It is measured
in Newtons.
Weight
Gravity
What is gravity?
Gravity is a force between
ALL objects!
We only really notice the
gravitational attraction
to big objects!
HELLO
Calculating weight
To calculate your weigh in other planets you have to apply the
following formula:
Weight (N) = mass (kg) x gravitational field strength (N/kg)
Example
The gravitational field strength on earth is around 10 N/kg.
What is your weight if your mass is 45 kg?
Weight (N) = mass (kg) x gravitational field strength (N/kg)
Weight (N) =
45 kg x 10 N/kg
Weight = 450 N
More examples…
Peter has a mass of 35 kg. What would it
be his weigh on the moon, where the
gravitational force is 1.62 N/kg
Weight = mass x gravitational force
W=
kg
W=
N
x
N/kg
So …Mass and Weight
Mass is the amount
of _________
(particles) in an
object. This stays the
same and is
measured in units of
mass e.g.
_______(kg) or grams
(g). Objects with a
_____ mass are more
difficult to move.
Weight the is the pull of _____ on the mass of an
object. On Earth, which has considerable gravity the
astronaut with a mass of _____kg has a weight of
______ Newtons (N). On the moon with less gravity his
weight is only ____N.
Mass and Weight
Mass is the
amount of matter
(particles) in an
object. This stays
the same and is
measures in units
of mass e.g.
kilograms (kg) or
grams (g). Objects
with a larger mass
are more difficult
to move.
Weight the is the pull of gravity on the mass of an
object. On Earth which has considerable gravity the
astronaut with a mass of 120kg has a weight of 1200
Newtons (N). On the moon with less gravity his weight
is only 200N.
SOLVING PROBLEMS…
 Practice by solving problems on the
Mathematical Entertainment 1 section.