Which best describes when a sonic boom occurs? a. when an object travels below the speed of sound b. when an object travels at or above the speed of sound c. when an object travels at the speed of sound d. when an object travels above the speed of sound

Mike and mitchell decide to have a foot race. they mark off a stretch of 100 yards, and recruit cindy to work the stopwatch. after running the race and looking at the results, cindy declared that mitchell was the fastest. so how did the boys times compare?

Which metals are called noble metals

With the largest atoms and the smallest number of valence electrons and with the smallest atoms and the greatest number of valence electrons are the most reactive. a. nonmetals; metals b. nonmetals; transition elements c. transition elements; metals d. metals; nonmetals