If a star appears to wobble back and forth, or its light seems to change in brightness, what might be the cause?​

Iron is a transition metal with multiple oxidation numbers. (answer the following) a. what is the iron (ii) ion? how does it differ from the iron (iii) ion? b. if iron were to bond with oxygen, predict the formula for each oxidation number of iron. c. how would each formula be named?

"if the pressure acting on an ideal gas at constant temperature is tripled, its volume isa) reduced to one-third. b) increased by a factor of three. c) increased by a factor of two. d) reduced to one-half"

Ball bearings are made by letting spherical drops of molten metal fall inside a talll tower-called a shot tower- and solidify as they fall. a-if a bearing needs 4.0 s to solidify enough for impact, how high must the tower be? b- what is the bearing's impact velocity?