2 Vectors with Angles acting on an object

In summary: This thread has been moved to the "Introductory Physics" section of "Homework & Coursework Questions", where it should have been posted in the first place. Carry on, and try to remember to post similar questions here in the future. :smile:
  • #1
JackandJones
16
0
Hey guys, I am having a little trouble determining the final answer to this question.

Basically an object is being pulled by two forces and I am suppose to find the Net Force

F1 = 12 N at an angle of 32 degrees (upwards)
F2 = 15 N at an angle of 24 degrees (downwards)

So what I did was split the two vectors and try to find Fnetx and Fnet y

For Fnetx = F1net + F2net

F1 = 12Cos(32)
F2 = 15 cos(24)

I added F1x and F2y and got
Fnetx = 23.87 N

For Fnety

F1y = 12sin32 = 6.36 N
F2y = 15sin24 = 6.10 N

I subtracted F1y-F2y because F2y is going in the negative direction so
Fnety = 0.26 N

I am not sure if I should add these together or use PT to get Fnet...then use Trig ratios to get the angle... ?

Any ideas? I appreciate the help!
 
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  • #2
You've now got the x and y components of a vector.
So how do you calculate the length and direction of the vector from them?

(You can't just add the lengths of the components - that would make no sense.)
 
  • #3
AJ Bentley said:
You've now got the x and y components of a vector.
So how do you calculate the length and direction of the vector from them?

(You can't just add the lengths of the components - that would make no sense.)

If I have Fnetx and Fnety

Would I use pythegorean theorem to find Fnet, and then Trig ratio to get the angle?
 
  • #4
Exactly that.
 
  • #5
Nytik said:
Exactly that.


Okay perfect However could you please explain why I would not substract the F1y by the F2y?

Because F2y is a downward motion, it would not be negative?
 
  • #6
You do subtract them; everything you have done up to this point is correct.
 
  • #7
Nytik said:
You do subtract them; everything you have done up to this point is correct.

Okay its just that the answer doesn't seem correct to me.

Fnetx = 23.87 N

Fnety = 0.26 N

Using PT:

Fnet = 23.87 N

Then then using Trig Ratios, the Angle = 0.62 degrees... which doesn't seem correct..?
 
  • #8
This thread has been moved to the "Introductory Physics" section of "Homework & Coursework Questions", where it should have been posted in the first place. Carry on, and try to remember to post similar questions here in the future. :smile:
 

1. What is the difference between a scalar and a vector quantity?

A scalar quantity has only magnitude (size or quantity), while a vector quantity has both magnitude and direction.

2. How do you represent a vector in mathematical notation?

A vector can be represented as an ordered pair of numbers (x, y) or as a column matrix [x y].

3. How do you add two vectors together?

To add two vectors, you can use the head-to-tail method or the parallelogram method. In the head-to-tail method, you place the tail of the second vector at the head of the first vector and draw the resultant vector from the tail of the first vector to the head of the second vector. In the parallelogram method, you draw the two vectors as adjacent sides of a parallelogram and the resultant vector is the diagonal of the parallelogram.

4. How do angles affect the magnitude and direction of a vector?

The angle between two vectors determines the magnitude and direction of their resultant vector. If the angle is 0 degrees, the resultant vector will have the same magnitude and direction as the two original vectors. If the angle is 90 degrees, the resultant vector will have a magnitude equal to the sum of the magnitudes of the two original vectors, and its direction will be perpendicular to both vectors.

5. How do you calculate the angle between two vectors?

The angle between two vectors can be calculated using the dot product formula: θ = cos⁻¹(a · b / |a||b|), where a and b are the two vectors and |a| and |b| represent their magnitudes.

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