Mastering Cross and Dot Products: A Guide for Test Review

In summary, the cross product and dot product are both vector operations, but they have different results. The cross product produces a new vector that is perpendicular to the input vectors, while the dot product produces a single value. The cross product can be calculated by taking the determinant of a 3x3 matrix, and it can be equal to zero if the input vectors are parallel or one of the vectors has a magnitude of zero. The dot product has many applications in physics and is related to the cross product in terms of magnitude and direction, as well as certain properties.
  • #1
1man
17
0
i'm reviewing for a test and I can't remember how to do the cross product of (2A)x(3B)
or how to find the angle theta when given components. or dot product: 2A . 3B
 
Physics news on Phys.org
  • #2
Are (2A) and (3B) normal vectors? If so, the link in your own post will tell you
how to do a cross product. If not, what are they?
 
  • #3
they are and i already know
Rz=Az+Bz
Ry=Ay+By
Rz=Az+Bz

but I am not sure how to do (2A)x(3C)
 
  • #4
or (2A)x(3B)
 

1. What is the difference between a cross product and a dot product?

A cross product is a vector operation that results in a vector perpendicular to the two input vectors, while a dot product is a scalar operation that results in a single value. In other words, a cross product produces a new vector that is perpendicular to both input vectors, while a dot product produces a single value that represents the projection of one vector onto the other.

2. How do you calculate the cross product of two vectors?

The cross product of two vectors, A and B, can be calculated by taking the determinant of a 3x3 matrix with the first row consisting of the unit vectors i, j, and k, and the second and third rows consisting of the components of vectors A and B, respectively. The result is a new vector in the direction perpendicular to both A and B.

3. Can a cross product be equal to zero?

Yes, a cross product can be equal to zero if the two input vectors are parallel or if one of the vectors has a magnitude of zero. This indicates that the two vectors are either pointing in the same direction or in opposite directions.

4. What is the significance of the dot product in physics?

The dot product has many applications in physics, including calculating work done by a force, determining the angle between two vectors, and finding the projection of one vector onto another. It is also used in the calculation of torque, energy, and power.

5. How are the cross product and dot product related?

The dot product of two vectors can be used to calculate the magnitude of the cross product, and the cross product can be used to find the direction of the dot product. Additionally, the properties of the cross product and dot product are related, such as the fact that the dot product of two perpendicular vectors is zero, while the cross product of two parallel vectors is zero.

Similar threads

  • Introductory Physics Homework Help
Replies
5
Views
768
  • Introductory Physics Homework Help
Replies
2
Views
967
  • Introductory Physics Homework Help
Replies
5
Views
697
  • Precalculus Mathematics Homework Help
Replies
5
Views
571
  • Introductory Physics Homework Help
Replies
32
Views
1K
  • Introductory Physics Homework Help
Replies
13
Views
2K
  • Introductory Physics Homework Help
Replies
3
Views
1K
Replies
10
Views
721
  • Linear and Abstract Algebra
Replies
33
Views
823
  • Calculus and Beyond Homework Help
Replies
19
Views
2K
Back
Top