A student runs 10.0 km east along the course, then turns around and runs 10.0 km west along the same path. The student returns to the starting point in 50 min.
a) What is the student's average speed?
b) The student's average velocity?

Average speed will be 3.3ms-1 and average velocity be 0ms-1

Explanation:

an ion is a charged atom or molecule. it is charged because the number of electrons do not equal the number of protons in the atom or molecule. an atom can acquire a positive charge or a negative charge depending on whether the number of electrons in an atom is greater or less then the number of protons in the atom.

if the thermos has a vacuum innner, then heat through conv currents and conduction are reduced = vacuum flask