Vectors

Vectors and Vector Addition

Fundamental Quantity = possess single unit.
Example :
Length, Mass, Distance, Displacement,
Time, Temperature, Height, Luminous intensity,

Derived Quantity = possess two or more units
Example :
Momentum, Force, Velocity, Speed, Work, Volume,
Area, Density, Weight, Specific Gravity, Power, Impulse,
Energy, Kinetic Energy, Potential Energy, Acceleration

Scalar Quantity = a physical quantity that is describe by as single number.
= a quantity that is completely described by its magnitude only.
Example :
Distance, Mass, Length, Height, Width, Temperature, Speed, Work, Volume, Area, Density, Specific Gravity, Amount of substance, Luminous intensity.

Vector Quantity = a quantity having both magnitude (the “how much” or “how big”
part) and direction.
Example :
Momentum, Force, Velocity, Electric Current, Displacement, Torque,
Weight, Specific Gravity, Power, Impulse, Acceleration

Vectors in the same direction

Add two vectors and copy the direction.

Vectors in opposite direction

Subtract the magnitude of the two vectors and copy the direction of the greater vector.

Three successive displacements A, B and C, and the
resultant or vector sum displacement R = A + B + C.

Example
The British Airways plane flies 20.0km in a direction 600 north of east, then 30.0km straight east, then 10.0km straight north. How far and in what direction is the plane from the starting point?
The components of A are
Ax = (20.0 km) (cos 600 ) = 10.0 km
Ay = (20.0 km) (sin 600 ) = 10.0 km
The components of all the displacements and the calculations can be arranged systematically, as in Table 1-2