Calculating Vector Components with given Magnitude and Direction

In summary, the problem involves finding the vector components of a force with a magnitude of 70N and an angle of 57.1 degrees measured counterclockwise from the positive y-axis. The correct angle for the formulas is actually measured from the positive x-axis, which is 147.1 degrees in this case. To find the components, you can either draw a triangle and use trigonometric functions, or adjust the formulas for the angle measurement from the y-axis. The x component is 38 and the y component is 58, and at least one of them will be negative due to the angle being in the second quadrant.
  • #1
rashad764

Homework Statement


F =(70N, 57.1∘counterclockwise from positive y−axis)[/B]
Find the vector components of F

Homework Equations


Sin and Cos of the angle[/B]

The Attempt at a Solution


x is component is 38 and y component is 58
how does the angle being counterclockwise affect my answer?
The answer above is wrong

Does the length of become F negative as well as the angle?
 
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  • #2
Have you drawn an image? Or more straight forward: how big is the angle measured form the positive x-axis as it is usually done? Do you know the formula for the components, given the angle and the length?
 
  • #3
rashad764 said:
Does the length of become F negative as well as the angle?
The length of a vector is always nonnegative, but in this case, at least one of the components will be negative. As already suggested, draw a sketch of the vector.
 
  • #4
fresh_42 said:
Have you drawn an image? Or more straight forward: how big is the angle measured form the positive x-axis as it is usually done? Do you know the formula for the components, given the angle and the length?
Don't you take the sin and cos of the angle, 70=x/cos57.1 then multiply 70(cos 57.1)
 
  • #5
rashad764 said:
Don't you take the sin and cos of the angle, 70=x/cos57.1 then multiply 70(cos 57.1)
Yes, but your angle is wrong. The angle for these formulas is measured from the x-axis, but you have a number measured from the y-axis.
 
  • #6
fresh_42 said:
Yes, but your angle is wrong. The angle for these formulas is measured from the x-axis, but you have a number measured from the y-axis.
How would I measure it from the x axis
 
  • #7
Sketch it, then you will see. How big is the difference between the two measurements? Of course you could as well calculate with the given angle, but then you will have to adjust the formulas to the new situation. This leaves us with the question: How is ##x= 70N \cdot \cos(57.1°)## found?
 
  • #8
fresh_42 said:
Sketch it, then you will see. How big is the difference between the two measurements? Of course you could as well calculate with the given angle, but then you will have to adjust the formulas to the new situation. This leaves us with the question: How is ##x= 70N \cdot \cos(57.1°)## found?
Do I draw the vector 57.1 degrees from x-axis then measure the difference
 
  • #9
rashad764 said:
57.1∘counterclockwise from positive y−axis
If it were from the x-axis, then the angle would be 57.1°
 
  • #10
You draw the vector at 57.1 degrees from the y-axis (counterclockwise, as given) and next measure the angle from the x-axis and put this new angle into the formulas. Or you draw a triangle with the given data and calculate the side lengths of this triangle plus adjust the signs according to the drawing.
 
  • #11
fresh_42 said:
You draw the vector at 57.1 degrees from the y-axis (counterclockwise, as given) and next measure the angle from the x-axis and put this new angle into the formulas. Or you draw a triangle with the given data and calculate the side lengths of this triangle plus adjust the signs according to the drawing.
the angle from the x-axis is 147.1
 
  • #12
rashad764 said:
the angle from the x-axis is 147.1
Right. And this is the angle your formulas are made for. Otherwise you would have had to use the triangle in the second quadrant (with different formulas) and use a positive y value and a negative x value.
 

1. How do I calculate the magnitude of a vector?

To calculate the magnitude of a vector, you can use the Pythagorean theorem, which states that the magnitude (or length) of a vector is equal to the square root of the sum of the squares of its components. In other words, if a vector has components x and y, its magnitude is equal to sqrt(x^2 + y^2).

2. What is the difference between magnitude and direction of a vector?

The magnitude of a vector refers to its length or size, while the direction of a vector refers to the angle that the vector makes with a reference axis. Both magnitude and direction are needed to fully describe a vector in two-dimensional space.

3. How do I find the components of a vector given its magnitude and direction?

To find the components of a vector, you can use trigonometric functions. If the magnitude of the vector is given as M and the direction as θ, the x-component can be calculated as M*cos(θ) and the y-component as M*sin(θ).

4. Can a vector have a negative magnitude?

No, a vector cannot have a negative magnitude. Magnitude is always a positive value that represents the length or size of the vector.

5. How do I represent a vector with its components?

A vector can be represented using its components in the form of an ordered pair (x, y), where x is the x-component and y is the y-component. This ordered pair is often referred to as the vector's position vector.

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