Year 9 Mass & weight homework
Planet

Diameter (Compared to Earth)

Gravitational Field Strength

Mercury

0.4

4 N/kg

Venus

0.9

9 N/kg

Earth

1

10 N/kg

Mars

0.5

4 N/kg

Jupiter

11

23 N/kg

Saturn

9

9 N/kg

Uranus

4

9 N/kg

Neptune

4

11 N/kg

Weight (N) = Mass (kg) x Gravitational Field Strength (N/kg)

Which planet has the largest gravitational field strength?

Which planet has the smallest gravitational field strength?

An object has a mass of 10 kg. How much will it weigh on:

Earth?

Mars?

Jupiter?

Calculate the mass of each of the following objects when the weight on Earth is:

20 N

100 N

2000 N

Mr. Snewin has a mass of 65 kg. What will his mass be on:

Mars?

Venus?

Mercury?
The mass of an object does not change if it were to visit another planet. This is because the number of atoms in the object stays the same. The weight of an object does vary from planet to planet due to varying gravitational field strength, g. The larger the gravitational field strength, the more an object will weigh.
Below is a table showing the gravitational field strength of the 8 planets in our Solar System.
Planet

Diameter (Compared to Earth)

Gravitational Field Strength

Mercury

0.4

4 N/kg

Venus

0.9

9 N/kg

Earth

1

10 N/kg

Mars

0.5

4 N/kg

Jupiter

11

23 N/kg

Saturn

9

9 N/kg

Uranus

4

9 N/kg

Neptune

4

11 N/kg

The weight of an object is calculated using the formula:
Weight (N) = Mass (kg) x Gravitational Field Strength (N/kg)

Which planet has the largest gravitational field strength?

Which planet has the smallest gravitational field strength?

An object has a mass of 10 kg. How much will it weigh on:

Earth?

Mars?

Jupiter?

Calculate the mass of each of the following objects when the weight on Earth is:

20 N

100 N

2000 N

An object weighs 500 N on Earth.

What is the mass of the object?

How much would it weigh on Neptune?

An object weighs 230 N on Jupiter.

What is the mass of the object?

How much would it weigh on Earth?

Mr. Snewin has a mass of 65 kg. What will his mass be on:

Mars?

Venus?

Mercury?
Answers
Planet

Diameter (Compared to Earth)

Gravitational Field Strength

Mercury

0.4

4 N/kg

Venus

0.9

9 N/kg

Earth

1

10 N/kg

Mars

0.5

4 N/kg

Jupiter

11

23 N/kg

Saturn

9

9 N/kg

Uranus

4

9 N/kg

Neptune

4

11 N/kg

The weight of an object is calculated using the formula:
Weight (N) = Mass (kg) x Gravitational Field Strength (N/kg)

Which planet has the largest gravitational field strength?
Jupiter

Which planet has the smallest gravitational field strength?
Mars and Mercury

An object has a mass of 10 kg. How much will it weigh on:

Earth – 10 kg x 10 N/kg = 100 N

Mars – 10 kg x 4 N/kg = 40 N

Jupiter – 10 kg x 23 N/kg = 230 N

Calculate the mass of each of the following objects when the weight on Earth is:

20 N 20 N / 10 N/kg = 2 kg

100 N 100 N / 10 N/kg = 10 kg

2000 N 2000 N / 10 N/kg = 200 kg

An object weighs 500 N on Earth.

What is the mass of the object? 500 N / 10 N/kg = 50 kg

How much would it weigh on Neptune? 50 kg x 11 N/kg = 550 N

An object weighs 230 N on Jupiter.

What is the mass of the object? 230 N / 23 N/kg = 10 kg

How much would it weigh on Earth? 10 kg x 10 N/kg = 100 N

Mr. Snewin has a mass of 65 kg. What will his mass be on:

Mars? 65 kg

Venus? 65 kg

Mercury? 65 kg
