Simply Lecture

Archimedes principle states that a body that is totally or partially (not fully) immersed in a fluid (liquid or gas) will experience an upward force (upthrust) which is equal with the magnitude (size) and weight of the body, it displaces.  The mathematical expression for Archimedes principle is given as : $$F = v*g*(\rho_f - \rho_o)$$ where, F = Buoyant force of the object in Newton (N) V = volume of the object (m^3) g = acceleration due to gravity = 9.80665 m/s^2} $\rho_f$ = density of the object $\rho_o$ = density of the fluid Illustration: From the above diagram, it is seen that when the stone is immersed in the liquid the volume of the water increases.

Basics of a magnet There are two poles of a magnet: 1. North Pole 2. South Pole The North Pole: The North Pole is that part of the magnet that is pointing at the Northern Cardinal of the earth. It is the part of the magnet, that is negative. The Southern Pole: The part of the magnet that is pointing at the Southern cardinal point of the earth is called the Southern Pole . It is the part of the magnet that is positive. Attraction and repulsion of a magnet Just as like charges repels and unlike charges attracts, so as it is in magnets.  The like poles of a magnet, repels each other; while the unlike poles of a magnet,  attracts each other. Take for example; the Northern pole of a magnet will attract the southern pole of another magnet, this is because they have different magnetic polarity. Also, the Northern pole of Magnet A will repel the Northern pole of Magnet B, this is because both two magnets have the same magnetic polarity.