Projectile Orbits and Satellite orbits

Newton had observed that any projectile launched horizontally is, in a sense, an Earth satellite.

A rock thrown from a tall building sails in a modest orbit that soon intersects the earth not far from its point of launch.

If the ball were fired more swiftly to start with, it would travel further.

Fut\rther increasing the speed would result in ever larger, rounder elliptical paths and more distant impact point.

Finally, at one particular launch speed, the ball would glide out just above the planet's surface

At successively greater launch speeds, the ball would resolve in ever-increasing elliptical orbit

This java applet let you change the launch speed by mouse click.

Then Press Start to fire the ball.

Press Reset to change parameters back to default values.

The red arrow represents the velocity vector.

Click right mouse button to stop the animation, press it again to resume.

Try to click the full checkbox, and find out what will happen.

Your suggestions are highly appreciated! Please click

Author:Fu-Kwun Hwang, ( click for more physics related java applet )
 Dept. of physics, National Taiwan Normal University
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