During takeoff, an airplane goes from 0 to 56 m/s in 9 s. how fast is it going after 4 s?

Give one example to show that when substances are mixed,it may result in a chemical or a physical change depending on the conditions.

An object in mechanical equilibrium is an object

What do the atoms of elements in the same group have in common? a. they have the same atomic numbers. b. they have the same average atomic masses. c. they have the same number of electron shells. d. they have the same number of electrons in their outermost shells.