Can Vectors with an angle 180(degrees+) have a negative magnitude?

In summary, the conversation discusses whether vectors with an angle measurement of 180+ degrees can have a negative magnitude. The individual is trying to find the components of a vector going 260 km at a 48 degree angle south of east and is unsure if the 260 km measurement is positive or negative due to the -48 degree angle. The equations used to find the components are also provided, along with a reminder to use the convention of counterclockwise being positive and clockwise being negative when measuring angles. The conversation concludes with a question about why sin is negative, which is explained by the vector being in the 4th quadrant.
  • #1
SaltyBriefs
10
0

Homework Statement


Can vectors with 180+(degrees) have a negative magnitude? I'm trying to find components of a vector that is going 260 km, 48 (degrees) south of east. So I'm confused whether the 260 is positive or not because of the -48 degrees.

Homework Equations


([itex]\vec{V}[/itex]) (sin[itex]\theta[/itex])
([itex]\vec{V}[/itex]) (cos[itex]\theta[/itex])

The Attempt at a Solution


(-260km)(sin(48)) or (260km)(sin(48)) =[itex]\vec{V}[/itex][itex]_{y}[/itex]

(-260km)(cos(48)) or (260km)(cos(48)) =[itex]\vec{V}[/itex][itex]_{x}[/itex]

Which one??
 
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  • #2
sin(x) = -sin(-x)

cos(x) = cos(-x)

Hope that helps.

Just use the convention that counterclockwise is postive and clockwise is negative in terms of measuring an angle.
 
Last edited:
  • #3
WatermelonPig said:
sin(x) = -sin(-x)

cos(x) = cos(-x)

Hope that helps.

Just use the convention that counterclockwise is postive and clockwise is negative in terms of measuring an angle.
Thank you this helped so much! But um just a quick question, why is sin negative? o_O
 
  • #4
SaltyBriefs said:
Thank you this helped so much! But um just a quick question, why is sin negative? o_O

Oh wait is this from cos, sin
and since it is in the 4th quadrant, y is negative (sin) and x is positive (cos)
 
  • #5


I would like to clarify that vectors with an angle of 180 degrees or greater can have a negative magnitude. This is because the magnitude of a vector is simply the length of the vector, which can be positive or negative depending on the direction of the vector. The angle of a vector only represents the direction, not the magnitude.

In the given problem, the 260 km is the magnitude of the vector, and the -48 degrees represents the direction. So, the magnitude is positive while the direction is negative. This means that the vector is going in a south of east direction, but the magnitude is still positive. Therefore, you should use the positive value of 260 km in your calculations for the components of the vector.

In general, when dealing with vectors, it is important to pay attention to both the magnitude and direction separately, as they are two distinct properties of a vector. I hope this helps clarify any confusion!
 

1. Can a vector have a negative magnitude?

Yes, a vector can have a negative magnitude. In fact, vectors can have negative, positive, or zero magnitudes depending on their direction and magnitude.

2. What does a negative magnitude represent in a vector?

A negative magnitude in a vector represents the direction of the vector. It means that the vector is pointing in the opposite direction of its positive magnitude.

3. Can a vector with an angle of 180 degrees have a negative magnitude?

Yes, a vector with an angle of 180 degrees can have a negative magnitude. This means that the vector is pointing in the exact opposite direction of its positive magnitude.

4. Why do some vectors have negative magnitudes?

Vectors can have negative magnitudes because they represent both direction and magnitude. A negative magnitude indicates that the vector is pointing in the opposite direction of its positive magnitude.

5. Can a vector with an angle of 180 degrees have a positive magnitude?

Yes, a vector with an angle of 180 degrees can have a positive magnitude. This means that the vector is pointing in the same direction as its positive magnitude but has a magnitude of zero.

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