why does a small pebble sin in water?

Critical mass is the of material required to produce a chain reaction. a.) minimum amount b.) atomic mass c.) precise amount d.) maximum amount

Which of the following statements correctly describes a transformer?

Mackinzie walks 4 blocks west, then 2 blocks south, then 4 blocks east, and, finally, 1 block south. what is the magnitude of her total displacement duringthis walk (in blocks)?