Gravitational Field Strength
Science: KS3, topic 3.5.16
Gravitational Field Strength
Gravitational field strength is how we describe the attraction between an object and the centre of a planet like Earth. The larger the gravitational field strength, the faster an object will fall.
Gravitational field strength
- The gravitation field strength is measured in Newtons per kilogram N/kg.
Size and gravity
- The gravitational field strength of an object depends on its size.
- The larger an object, the more massive its gravitational pull.
Gravity on Earth
- The gravitation field strength on Earth is 10 N/kg.
- So a 1kg mass will accelerate with a force of 10N.
Moon and Jupiter
- The gravitation field strength of the Moon is 1.6 N/kg.
- The gravitation field strength of Jupiter is 25 N/kg.
Calculating weight
- The equation to calculate weight is:
- Weight (N) = mass (kg) x gravitational field strength (N/kg).
- An object with a mass of 20 kg on Earth would have a weight of 200N.
- 20kg × 10N/kg.
Weight on the Moon
- An object with a mass of 20 kg on the Moon would have a weight of 32N.
- 20kg × 1.6 N/kg.
Weight in space
- Your mass (kg) will remain the same on all planets in our solar system.
- You travel the solar system.
- So your weight would depend on the size of the planet you are on.
Rearranging the equation
- The calculation can be rearranged to work out mass:
- Mass (kg) = weight (N) ÷ gravitational field strength (N/kg).
Test yourself on Gravitational Field Strength
What are the units of gravitational field strength?
Gravitational Field Strength
Select the correct statement in each pair
Why would a ball fall faster on Jupiter than on Earth?