In my hand I have two coins that are newly minted. Together, they total 30 cents. One isn’t a nickel. What are the coins?

When a book falls from a shelf to the ground without anyone pushing on it, no work is done on the book. true or false

Hydrogen and helium are both members of?

Scientists follow specific processes in order to determine valid explanations and conclusions from observations. david observed strange lights in the sky above his home outside of roswell, new mexico. the only explanation that makes sense to him is that there are ufos in the area. what should david do next to verify his explanation?