chapter 3 vectors in physics dr. haykel abdelhamid elabidi 1 st /4 th week of october 2013/dhh 1434
TRANSCRIPT
Units of Chapter 3
• Scalars versus vectors
• The components of a vector
• Adding and subtracting vectors
• Scalar product or dot product
• Vector product or cross product
Scalars versus VectorsA scalar is a number with units. It can be positive, negative or zero.
Scalar quantitiesMasse
Temperature
Energy
Power
Speed
Vector quantitiesVelocity
Acceleration
Displacement
Force
Field
A vector is a mathematical quantity with both a magnitude and a direction
Your home
School?
To describe where the shool is located versus your home, It is not sufficient to give the distance between them. we have to give the distance and the direction.
School?
School?
2 km
2 km
2 km
The components of a vectorExersise 3-2 page 61:
A
A vector is defined by its magnitude and direction, regardless of its location
Adding and subtracting vectorsAdding Vectors Using Components:
1. Find the components of each vector to be added.
2. Add the x- and y-components separately.
3. Find the resultant vector.
ABBAC
Adding and subtracting vectors
Subtracting Vectors: The negative of a vector is a vector of the same magnitude pointing in the opposite direction. Here D= A B
BABAD
Multiplying vector by 3 increase its magnitude by a factor of 3, but does not change its direction. If it is multiplied by -3, its magnitude is increases by 3 but it will has the opposite direction.
Multiplying vector by scalar
The result of the vector product of two vectors and is a vector that is perpendicular to the plan of the two vectors:
Vector product or cross product
A
B