PHYS 2211 Module 2.4

Products of Vectors

Recommended Reading

2.4 Products of Vectors

Learning Objectives

By the end of this section, you will be able to:

  • Explain the difference between the scalar product and the vector product of two vectors.
  • Determine the scalar product of two vectors.
  • Determine the vector product of two vectors.
  • Describe how the products of vectors are used in physics.

Scalar Product (or the Dot Product)

Practice!

Practice 2.4.1

What is the dot product ?
(a) (120 m2)cos 78.0°
(b) (120 m2)sin 78.0°
(c) (120 m2)cos 62.0°
(d) (120 m2)sin 62.0°
(e) Something else

Discuss!

Consider how you would answer this question. Then bring this to class for a group discussion.

Based on the vectors in the diagram above, find the following scalar (dot) products:

Vector Product (or the Cross Product)

Practice!

Practice 2.4.2

What is the cross product ?
(a) (96.0 m2) sin 25.0°
(b) (96.0 m2) cos 25.0°
(c) -(96.0 m2) sin 25.0°
(d) -(96.0 m2) cos 25.0°
(e) Something else

Discuss!

Consider how you would answer this question. Then bring this to class for a group discussion.

Based on the vectors in the diagram above, find the following scalar (dot) products: