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Gravitational Fields

Gravitational fields and field strength

  • 3 things to know
  • Papers 1, 2 and 3

Overview

Recall questions on modelling a sphere as a point mass, field lines, and g as force per unit mass.

What you need to know

Answer each one before you reveal it.

Your recallNot started
Key term

State the unit of gravitational field strength.

Key term

What phenomenon do fields provide a model for, and what does this mean?

Key term

In which direction do gravitational field lines point around a mass?

Questions from this subtopic

Each one with the model answer underneath.

  1. 1

    What property must an object possess in order to produce a gravitational field?

    Model answer

    Mass

  2. 2

    When modelling the gravitational effects of a spherical object, where is its mass considered to be concentrated?

    Model answer

    At a single point located at the centre of the sphere

  3. 3

    Under what condition is it valid to treat a spherical mass as a point mass at its centre?

    Model answer

    When calculating gravitational effects at positions outside the sphere

  4. 4

    What are gravitational field lines used for?

    Model answer

    To map and represent gravitational fields

  5. 5

    In which direction do gravitational field lines point around a mass?

    Model answer

    Towards the centre of the mass (in the direction a test mass would accelerate)

  6. 6

    Explain why gravitational field lines around an isolated planet are drawn pointing inward rather than outward.

    Model answer

    Because a test mass placed in the field would experience a force directed towards the planet's centre, and field lines show the direction of this force

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A wave.
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Density means mass per unit volume.
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