Which two phrases describe the location where the force of an earthquake is felt most strongly?
A. The point on Earth's surface directly above where the rock breaks
B. The focus
I C. The point where the rock breaks underground
D. The epicenter

What happened in 2012 and how does it illustrate the importance of understanding the sun and how it works?

Particle model to predict what will happen if a sharp object creates a hole in the soccer ball

Ammonium perchlorate nh4clo4 is the solid rocket fuel used by the u.s. space shuttle. it reacts with itself to produce nitrogen gas n2 , chlorine gas cl2 , oxygen gas o2 , water h2o , and a great deal of energy. what mass of nitrogen gas is produced by the reaction of 2.1g of ammonium perchlorate?