Plotting graph

Is it possible that i use a sensor to sense the speed of an object and use Visual Basic to plot the graph? How do I go about doing it?

Sure. Which part do you need help with, reading the sensor or drawing a graph?

both.. is it possible to use RFID? any website to recommend so that I can take a look and learn more about it?

For RFID you'd need the specs on the RFID reader - is it serial (or USB looking like a serial port)? Is it something else? The manufacturer can make a device look like almost anything (we once made a tape drive look like an infinitely long disk track, so that we could use off the shelf technology).

For a preliminary look, do a Google search on RFID devices. You'll grow old before you've read half of them.

for plotting a graph see Woka's suite which contains a simple graph plotter
http://www.vbforums.com/showthread.php?t=328044

RMChart could be useful too, it's a free control, there are online examples in that site also.