"A vector whose magnitude is One is called unit vector .it is used to find the direction of a vector . the formula for a unit vector is, A=`A^/|A| . position vector: it is a vector that describe the location of a particles with respect to origin . the position vector "r" of point p(a, b) in X-Y plan is given by. a =ai^ +bj^ +ck^. where k^ is the unit vector along z-axis.in three dimension , the position and r^ from origin will a^=a i^+bj^+ck^ . where i^ ,j^ and k^ are the unit vector along x,y and z- axis respectively. component of a vector : "the part of a vector effective in a particular direction is called component of a vector . usually a vector has two or more components , one along is x-axis is called horizontal component and other along y-axis is called vertical component" . Defined Equilibrium : ? Equilibrium ; "if a body , under the action of a number of forces , is at rest or moving with uniform velocity , is said to be equilibrium". (1): static equilibrium : if a body is at rest , is said to be in static equilibrium. for example, book lying on the table. (2): Dynamic equilibrium; if a body is moving with uniform velocity, or rotating with uniform angular velocity, it is said to be in dynamic equilibrium . for example, jumping paratrooper . vector oR Cross products : ? "when the product of two vectors results into a vector quantity , then the product is called vector product . the vector product between two vectors can be expressed as by putting a cross (×) and can be written as" A ×B " . So this product is also called cross product. Example , (1) : t^= r^× F^ where torque is a vector because it is a cross product of momentum arm and force. (ii) : L^= r^×p^ , where Angular momentum is a vector because it is a cross product of perpendicular distance and momentum. (iii) : F^ =q (v^×B^ ) where force is a vector because it is the cross -product of velocity and magnetic field.
