How long will it take to travel 2000 Km at 500 Km
a.100,000 hr
b.2500 Km
c.4 hr

What type of electromagnetic wave is used in security pens? a. x-rays c. microwaves b. visible light d. ultraviolet radiation select the best answer from the choices provided

The ozone hole appears in antarctica during

Which is not an example of how an object gains elastic potential energy by stretching? a. jumping on a pogo stick b. pulling on a rubber band c. jumping on a trampoline