Questions on torque and cross products

In summary: F, which will give us a vector perpendicular to both r and F. Using the right-hand rule, we can determine the direction of this vector and then use the equation to calculate its magnitude.I hope this summary has helped you understand the concepts and equations involved in solving questions on vector product. Remember to always draw diagrams and use the right-hand rule to determine directions, and you will be able to solve these types of questions with ease.In summary, vector product is an operation that results in a vector that is perpendicular to the two vectors being multiplied. Its magnitude is equal to the product of the magnitudes of the two vectors multiplied by the sine of the angle between them. To find the direction of the resulting vector, we can use the
  • #1
prime-factor
77
0

Homework Statement



Hello. I have three questions on vector product that I am having problems with.
I have attached the images for these questions.

Homework Equations



Vector Product:

a x b = lal lbl sin (theta) n

or i, j, k method

Area of a triangle:

(1/2) l a x b l

Torque = l r x F l, where r = vector from force, F = force vector

The Attempt at a Solution



I am confused about these questions. I would really appreciate your help in understanding how to work them out.

Thanks in advance.
 

Attachments

  • Question 1.png
    Question 1.png
    4.9 KB · Views: 376
  • Question 2.png
    Question 2.png
    7 KB · Views: 385
  • Question 3.png
    Question 3.png
    8.9 KB · Views: 358
Physics news on Phys.org
  • #2


Dear student,

I am happy to help you with your questions on vector product. I understand that it can be a challenging concept to grasp, but with practice and understanding of the underlying principles, you will be able to solve these questions easily.

Firstly, let's review the equation for vector product:

a x b = lal lbl sin (theta) n

This equation represents the vector product, also known as the cross product, of two vectors a and b. The result of this operation is a vector that is perpendicular to both a and b, and its magnitude is equal to the product of the magnitudes of a and b multiplied by the sine of the angle between them. The direction of the resulting vector is determined by the right-hand rule, where you point your fingers in the direction of a and then curl them towards b. Your thumb will then point in the direction of the resulting vector.

Now, let's apply this to the first question. We are given two vectors a and b, and we are asked to find their cross product. Remember that the resulting vector is perpendicular to both a and b, so it will be in the direction that is perpendicular to the plane containing these two vectors. To find the direction, we can use the right-hand rule as described above. Once we have the direction, we can use the equation to calculate the magnitude of the resulting vector.

Moving on to the second question, we are given three vectors a, b, and c, and we are asked to find the area of the triangle formed by these vectors. The formula for the area of a triangle using vector product is:

(1/2) l a x b l = (1/2) l c l l sin (theta) l

where c is the third side of the triangle and theta is the angle between a and b. This formula comes from the fact that the area of a triangle is equal to half the product of its base and height, and in this case, the base is the magnitude of c and the height is the sine of the angle between a and b.

Finally, in the third question, we are asked to find the torque exerted by a force on a lever. The formula for torque is:

Torque = l r x F l

where r is the vector from the point of rotation to the point of application of the force, and F is the force vector. To find the torque, we need to find the cross product of r
 

1. What is torque?

Torque is a measure of the force that can cause an object to rotate around an axis. It is a vector quantity, meaning that it has both magnitude and direction. It is typically measured in units of Newton-meters (Nm).

2. How is torque calculated?

Torque is calculated by multiplying the force applied to an object by the distance from the point of rotation to the point where the force is applied. This distance is known as the lever arm. Mathematically, torque = force x lever arm.

3. What is the difference between torque and force?

Force is a push or pull that can cause an object to accelerate, while torque is a twisting force that causes an object to rotate. Force is a vector quantity, while torque is a vector quantity. Additionally, force is measured in units of Newtons (N), while torque is measured in units of Newton-meters (Nm).

4. How does cross product relate to torque?

The cross product is a mathematical operation that combines two vectors to produce a third vector that is perpendicular to the original two. In the context of torque, the cross product is used to calculate the direction and magnitude of the torque vector, which is perpendicular to both the force vector and the distance vector.

5. What are some real-world applications of torque and cross products?

Torque and cross products are used in various industries and technologies, including engineering, physics, and mechanics. Some examples of real-world applications include the design of motors and engines, understanding the stability of structures, and calculating the forces acting on a rotating object.

Similar threads

  • Calculus and Beyond Homework Help
Replies
5
Views
979
  • Calculus and Beyond Homework Help
Replies
1
Views
769
  • Calculus and Beyond Homework Help
Replies
11
Views
430
  • Introductory Physics Homework Help
Replies
11
Views
232
  • Calculus and Beyond Homework Help
Replies
2
Views
1K
  • Calculus and Beyond Homework Help
Replies
5
Views
1K
  • Introductory Physics Homework Help
Replies
4
Views
342
  • Calculus and Beyond Homework Help
Replies
4
Views
821
  • Calculus and Beyond Homework Help
Replies
2
Views
7K
  • Calculus and Beyond Homework Help
Replies
1
Views
563
Back
Top