Physlet

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Planetary motion (ellipse)

A planet (green) orbits a star (yellow) as shown in the  animations.  Restart. View the animation and observe how the velocity of the planet changes during its orbit. Click here to view the velocity vector (blue) and acceleration vector.

What general obervations can you make about the directions of the velocity and acceleration vectors at all points along the path?

What do you observe about the angle between the velocity and acceleration vectors when the planet is speeding up?

What do you observe about the angle between the velocity and acceleration vectors when the planet is slowing down?

At what points are the velocity and acceleration vectors perpendicular?

Physlet authored by Aaron Titus with support by the National Science Foundation under Grant No. DUE-9952323 and placed in the public domain. It can also be found in the book Physlet Physics by Wolgang Christian and Mario Belloni.

are scriptable Java Applets written by Wolfgang Christian of Davison College.