PLEASE HELP ME I DONT UNDERSTAND THIS AND THIS IS TIMED In an experiment, a rubber stopper is attached to one end of a string. The stopper is whirled in a horizontal circular path of a diameter of 1.0 meter at a constant speed. The stopper completes one revolution in 0.2 seconds. Approximately what is the magnitude of the stoppers speed?

A) 3.1 m/s
B) 6.3 m/s
C) 16 m/s
D) 31 m/s

Listed following are various physical situations that describe how light interacts with matter. match these to the appropriate category. 1) transmission? -visible light meets clear glass -visible light does not pass through a black wall -red light hits a red sweatshirt -light comes from your computer screen -cell phone signals pass through walls -blue light hits a red sweatshirt -white light hits a white piece of paper -light comes from a light bulb