Kylie asked in Science & MathematicsPhysics · 8 months ago

Help with vectors for physics homework?

2. Consider the two vectors,

A = 16.5x + 35.5y

B = 5.7x - 21y

2. A) What is the magnitude of the vector A - B? 

I already found the answer to this, 57.5, but can't figure out the rest

2. B) What is the angle of the vector A - B, measured counterclockwise in degrees from the positive x-axis? 

2. C) What is the magnitude of the vector 3A + B? 

2. D) What is the angle of the vector 3A+B, measured counterclockwise in degrees from the positive x-axis? 

2 Answers

Relevance
  • Vaman
    Lv 7
    8 months ago

    A = 16.5x + 35.5y

    B = 5.7x - 21y

    A-B= (10.8, 56.50) Magnitude =sqrt(10.8^2+56.5^2)=57.5

    magnitude A=39.15,  B=21.75.

    cos a= A dot B/(AB)=0.06. a=1.51 degrees

    Rest you can do.

  • ?
    Lv 7
    8 months ago

    A-B = <10.8 , 56.5>

    b/

    angle θ , with tan(θ) = 56.5/10.8 ---> θ = 79.2 degrees

    c/

    3A+B = 3<16.5, 35.5> + <5.7 , -21> = <55.2 , 85.5>

    --> ||3A+B||=101.8

    d/

     tan(θ) = 85.5/55.2 ---> θ = 57.2 degrees

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