first we make a U turn and travel towards home in t = 20 s
so the distance of home from initial position is


Now after picking up the book we travel back with speed 20 m/s
so again after t = 20 s the displacement is given as

so the net displacement is given as


so it will be displaced by total displacement 200 m
The slope of the line is
(change in ' y ' between the ends) / (change in ' x ' between the ends)
Slope = (630g - 0) / (70 cm^3 - 0)
Slope = (630 / 70) g/cm^3
<em>Slope = 9.0 g/cm^3</em>
Alkali metals: left column of your periodic table (not hydrogen, but anything below it). They have one valence electron, which they are happy to share in a reaction.
Halogens: second column from the right of your periodic table. They are one electron short of a full shell, so they are reactive in the opposite way that alkalis are--they want electrons.
Atomic number (number of protons) is the big number on the periodic table square. Hydrogen's is 1.
Atomic mass is a little number down below. For example, Hydrogen's is 1.008.
Neutrons are a tricky subject, because different isotopes of the same element can have different numbers of neutrons. You can't generally get this from the atomic mass, because the atomic mass is a weighted average of naturally occurring isotopes. Hydrogen can have 0,1, or 2 neutrons. To answer this, you'd have to choose a particular isotope from the table of isotopes (a completely different chart from the periodic table) which has a certain number of neutrons: n = weight - Z.
Valence electrons are the electrons in the outermost shell. (The column of the table).
<span>
Number of principal shells is the row of the periodic table. </span>
[two waves] pass a point [every second]... The answer is in the question (B)
Answer:
advance in the understanding of cellular movement
Explanation:
All organisms are formed from cells, "understanding how cells are able to interact with other cells during development helps us understand how tissues and organs are established and, consequently, how the shape arises in embryos," explains Germán Reig