On some toll roads, the ticket is stamped with the time you enter the toll road and the time that you exit. How can the toll taker determine if you were speeding?

i guess that visual aids present persuasive examples to what you are presenting, some factors would be theme (does it fit with the color, information, what you are presenting), size (can you see it, is it a big enough span of data/information), and overall look of the visual aid.

hope this : )

gravitational energy

electrical energy

kinetic energy

ligh energy