Weight and Mass
N/kg
kg
N
weight = mass  gravitational field strength
W=mg
Not so Tricky
On Earth, the gravitational field strength, g, is 9.81 N/kg
1. Calculate the weight of the following objects on Earth:
a. A suitcase of mass 22 kg
b. A car of mass 1110 kg
c. A pencil case of mass 0.3 kg
d. A bag, of mass 1.2 kg, containing 5 books, each of 0.5kg
e. A tennis ball of mass 58.0 grams
HINT: Be sure to
convert the units first
2. Calculate the mass of the following objects (the weight as measure on Earth is given):
a. A girl with a weight of 490 N
b. A bag of sugar with a weight of 9.81 N
c. A motorbike with a weight of 2.5 kN
Trickier
3. Complete the following table:
Weight, W
60 kg
Girl on a scooter
Moped and rider
g on surface of
Ceres (Dwarf planet)
1800 N
28 N
100 kg
5500 kN
3 kN
Gravitational Field
Strength, g
9.81 N/kg
9.81 N/kg
200 milli-grams
Dose of medicine
Airbus A380 (maximum
take-off weight)
g on surface of a
White-Dwarf star
Mass, m
9.81 N/kg
9.81 N/kg
1 gram
4. An astronaut, with her space-suit, has a mass of 80 kg. The gravitational field strength on
the Moon is one sixth that on Earth.
a. Calculate the astronaut’s weight on the Moon.
b. State what happens to the astronaut’s mass on the Moon.
c. The astronaut travels to Mars where her weight becomes 296 N. Calculate the
gravitational field strength on the surface of Mars.
d. Suggest what you think happens to her weight if she travelled to the surface* of
Jupiter. Explain you answer.
(*i.e. the top of Jupiter’s very thick atmosphere)