## Exploration 12.3: Properties of Elliptical Orbits

Please wait for the animation to completely load.

A planet (green) orbits a star (yellow) as shown in the animation. Restart.

On a piece of paper sketch vectors for the velocity, radial component of acceleration, and tangential component of acceleration for the planet. The length of the vectors should be indicative of the magnitude of the vectors.

- Rank the points, A–E, according to the speed of the planet at that point.
- Rank the points, A–E, according to the gravitational potential energy of the planet.
- Rank the points, A–E, according to the kinetic energy of the planet.
- Rank the points, A–E, according to the total energy of the planet.
- At which of the points, A–E, is the planet's acceleration in the same direction as the velocity?
- What can you say about the direction of the planet's acceleration at any point on its path? Would you call this acceleration a tangential acceleration or a radial acceleration?

Click here to view the velocity vector (blue) and acceleration vector (red). Compare what you see to your answers (a)–(f).

Exploration authored by Aaron Titus with support by the National Science Foundation under Grant No. DUE-9952323 and placed in the public domain.

Physlets were developed at Davidson College and converted from Java to JavaScript using the SwingJS system developed at St. Olaf College.

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