Three vectors A, B, and C each have a magnitude of 50m and lie in the x-y plane. Their directions relative to the positive x-axis are 30 degrees, 195 degrees, and 315 degrees, respectively. What are (a) the magnitude and (b) the angle of the vector A + B + C, and (c) the magnitude and (d) the angle of A-B+C? What are the (e) magnitude and (f) angle of the fourth vector D such that (A+B)

Respuesta :

Answer:

a) [tex]R_{A+B+C} =\sqrt{(30.3603)^{2}+(-23.2963)^{2}  } =38.2683 m[/tex]

b) Θ=[tex]tan^{-1} (\frac{R_{y} }{R_{x} } )=tan^{-1} (\frac{-23.2963}{30.3603} )=142.5[/tex]º

c) [tex]R_{A-B+C} =\sqrt{(126.953)^{2}+(2.5856)^{2}  } =126.97 m[/tex]

d) β=[tex]tan^{-1} (\frac{R_{y} }{R_{x} } )=tan^{-1} (\frac{2.5856}{126.953} )=1.16[/tex]º

e) [tex]D=\sqrt{(-5)^{2} +(12.059)^{2} } =13.0545m[/tex]

f) ∅=[tex]tan^{-1} (\frac{R_{y} }{R_{x} } )=tan^{-1} (\frac{12.059}{-5} )=111.66[/tex]º

Explanation:

First of all, we need to establish our vectors and it's directions:

A=50 m, 30º

B=50 m, 195º

C=50 m, 315º

Now that we have the three vectors, we need to calculate the x and y components:

[tex]A_{x} =50cos(30)=25\sqrt{3}m[/tex]

[tex]A_{y} =50sin(30)=25m[/tex]

[tex]B_{x} =50cos(195)=-48.2963 m[/tex]

[tex]B_{y} =50sin(195)=-12.941 m[/tex]

[tex]C_{x}=50cos(315)=25\sqrt{2}m[/tex]

[tex]C_{y}=50sin(315)=-25\sqrt{2}m[/tex]

Now, that we have the components, we can calculate the resultant's components:

[tex]R_{x} =A_{x} +B_{x} +C_{x}=25\sqrt{3}  +(-48.2963)+25\sqrt{2} =30.3603m[/tex]

[tex]R_{y} =A_{y} +B_{y} +C_{y}=25 +(-12.941)+(-25\sqrt{2}) =-23.2963m[/tex]

To find the resultant of the vector A+B+C we need to do the following steps:

a) [tex]R_{A+B+C} =\sqrt{(30.3603)^{2}+(-23.2963)^{2}  } =38.2683 m[/tex]

To find the angle it's necessary to use [tex]tan^{-1}[/tex]:

b) Θ=[tex]tan^{-1} (\frac{R_{y} }{R_{x} } )=tan^{-1} (\frac{-23.2963}{30.3603} )=142.5[/tex]º

To find the resultant of the vector A-B+C we need to do the following steps:

[tex]R_{x} =A_{x} -B_{x} +C_{x}=25\sqrt{3}  -(-48.2963)+25\sqrt{2} =126.953m[/tex]

[tex]R_{y} =A_{y} -B_{y} +C_{y}=25 -(-12.941)+(-25\sqrt{2}) =2.5856m[/tex]

c) [tex]R_{A-B+C} =\sqrt{(126.953)^{2}+(2.5856)^{2}  } =126.97 m[/tex]

To find the angle it's necessary to use [tex]tan^{-1}[/tex]:

d) β=[tex]tan^{-1} (\frac{R_{y} }{R_{x} } )=tan^{-1} (\frac{2.5856}{126.953} )=1.16[/tex]º

To find D=A+B it's important to follow the following steps:

[tex]R_{x} =A_{x} +B_{x} =25\sqrt{3}  +(-48.2963)=-5m[/tex]

[tex]R_{y} =A_{y} +B_{y} =25 +(-12.941)=12.059m[/tex]

e) [tex]D=\sqrt{(-5)^{2} +(12.059)^{2} } =13.0545m[/tex]

f) ∅=[tex]tan^{-1} (\frac{R_{y} }{R_{x} } )=tan^{-1} (\frac{12.059}{-5} )=111.66[/tex]º