Chapter 3 Vectors in Physics Dr. Haykel Abdelhamid Elabidi 1 st /4 th week of October 2013/DhH 1434

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 Vectors A scalar is a number with units. It can be positive, negative or zero. Scalar quantities Masse Temperature Energy Power Speed Vector quantities Velocity 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? 2 km

The components of a vector A vector in xy plane can be resolved in two components.

The components of a vector

Exersise 3-2 page 61: A vector is defined by its magnitude and direction, regardless of its location

The components of a vector

Adding and subtracting vectors Adding 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.

Adding and subtracting vectors Subtracting Vectors: The negative of a vector is a vector of the same magnitude pointing in the opposite direction. Here

Example: Adding and subtracting vectors

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 scalar product of two vectors and is a scalar: Scalar product or dot product

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

Thank you for your attention See you next time Inchallah