8867 / 2027

Chapter 7

Circular Motion

Separate the direction of motion from the direction of acceleration, then choose the actual forces and the correct radius.

Connect angular and linear quantities to a force model, with each equation tied to its conditions.

Radians, angular velocity, inward acceleration, radial force, Newtonian gravitation, near-Earth field strength, circular orbits and geostationary satellites. For 8867 (2027).

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  1. Describe a turn

    Use radians, period and frequency to connect angular and tangential speeds, and measure repeated turns.

  2. Why acceleration points inward

    Construct a change of velocity and distinguish a finite-interval average from instantaneous inward acceleration.

  3. Choose the radial force

    Resolve actual forces in a tether and conical pendulum, and interpret force-speed data.

  4. Gravity and the near-Earth field

    Use centre separation in Newtonian gravitation and explain why near-surface field strength is approximately constant.

  5. Circular orbits and geostationary satellites

    Use gravity as the inward resultant, distinguish altitude from radius and explain the conditions for a fixed apparent position.