Click anywhere on the applet to place your planet. Then drag to
give it an initial velocity.
Here are several orbits you can try.
Planet 
Distance From Sun

Average Speed

Length of Year

Mercury 
58 x 10^{6} km

48 km/sec

88 days

Venus 
108 x 10^{6} km

35 km/sec

226 days

Earth 
150 x 10^{6} km

30 km/sec

365 days

Mars 
228 x 10^{6} km

24 km/sec

694 days

Clicking on "Show Kepler's Law" will mark off the orbit in equal time segments for the next orbit created. Each segment created has the same area. Click here to see some example orbits.
Can you create orbits of other shapes? Elliptical? Hyperbolic?