Intro physics question involving magnitudes and vectors

In summary, the conversation discusses a scenario where a person is hanging from a chinning bar with their arms at right angles to each other. The magnitudes of the forces exerted by both arms are equal and together they support the person's weight of 620 N. The conversation also includes a sketch of the two force vectors for the arms and their resultant. Using components, the magnitude of each arm force vector is calculated to be 438 N. Despite a request for a second opinion, the person's calculations are confirmed to be correct.
  • #1
Kevin Bertham
2
0
You’re hanging from a chinning bar, with your ;arms at right angles to each other. The magnitudes of the forces exerted by both your arms are the same, and together they exert just enough upward force to support your weight, 620 N. (a) Sketch the two force vectors for your arms, along with their
resultant, and (b) use components to find the magnitude of each of the two “arm” force vectors.

So i drew the triangles out with 310 across the x-axis and 620 down.

The 90 degree angle as well as the two 45`s . I went to find the H which is cos 45= O/H , multiply by H on both sides so its H*cos45= 310 divide both by cos 45 which leaves you with H=310/cos45 which leaves with 438 N as the resultant. That is what i did anyway I don't think i am correct but if someone could give this a peak.
 
Physics news on Phys.org
  • #2
Want a second opinion ? You're still correct !
 
  • #3
lol they said i needed to follow the posting guidelines
 
  • #4
Still true: use the template (you should also READ the guidelines ;-) )
 
  • #5


Your approach is correct. The magnitude of each arm force vector can be found using the Pythagorean theorem:
a^2 + b^2 = c^2
where a and b are the horizontal and vertical components of the force vector, and c is the magnitude.
In this case, a = 310 N and b = 620 N.
So, c = √(310^2 + 620^2) = 438 N.
Therefore, the magnitude of each arm force vector is 438 N.
Your sketch should show the two arm force vectors, each with a magnitude of 438 N, and the resultant force vector, pointing upwards, with a magnitude of 620 N.
Great job!
 

Related to Intro physics question involving magnitudes and vectors

1. What is the difference between magnitude and vector in physics?

In physics, magnitude refers to the size or quantity of a physical quantity, such as speed or force. On the other hand, a vector has both magnitude and direction, and is used to represent physical quantities that have both size and direction, such as velocity or acceleration.

2. How do you calculate the magnitude of a vector?

The magnitude of a vector can be calculated using the Pythagorean theorem, which states that the magnitude (or length) of a vector in two or three dimensions is equal to the square root of the sum of the squared components of the vector. In other words, the magnitude of a vector can be calculated as the square root of the sum of the squares of its x, y, and z components.

3. Can vectors with different magnitudes be added together?

Yes, vectors with different magnitudes can be added together. When adding vectors, their magnitudes are added together while taking into account their directions. This is known as vector addition and is an important concept in physics and other sciences.

4. How do you represent vectors graphically?

Vectors are often represented graphically by arrows, where the length of the arrow represents the magnitude of the vector and the direction of the arrow represents the direction of the vector. The starting point of the arrow is often placed at the origin (0,0) of a coordinate system.

5. Can you have a negative vector magnitude?

Yes, you can have a negative vector magnitude. This occurs when the vector is pointing in the opposite direction of a positive vector. In other words, a negative vector magnitude means that the vector is pointing in the opposite direction of the positive direction, but still has the same magnitude as the positive vector.

Similar threads

  • Introductory Physics Homework Help
Replies
14
Views
375
  • Introductory Physics Homework Help
Replies
5
Views
864
  • Introductory Physics Homework Help
Replies
3
Views
2K
  • Introductory Physics Homework Help
Replies
11
Views
842
Replies
3
Views
168
  • Introductory Physics Homework Help
Replies
3
Views
6K
  • Introductory Physics Homework Help
Replies
6
Views
988
  • Introductory Physics Homework Help
Replies
2
Views
2K
  • Introductory Physics Homework Help
Replies
2
Views
888
  • Introductory Physics Homework Help
Replies
1
Views
3K
Back
Top