What happens as a roller coaster car rises up the first hill of its tracks

Asample of radium-226 will decay 1/4 of its original amount after 3200years. what is the half-life of radium-226?

Long term exposure to waves can cause sunburns and skin cancer. a) visible b) infrared c) gamma rays d) ultraviole

Free answer. the treaty of versailles ended world war i, but some of the terms of the treaty contributed to the beginning of world war ii. which was one of the terms of the treaty? the answer would be "germany was forces to pay reparations to the allied countries.". i hope this .