Question

Suppose that the sum of the three vectors u, v, and w shown in the figure is the zero vector. If w = 10 find u and v.

Answer 1

a. The value of v is 9.2

b. The value of u is 9.9

What are vectors?

Vectors are physical quantities that have both magnitude and direction

How to find the value of vectors u and v?

Since we have vectors

• u at 70° to the x-axis

• v at 47° to the x-axis and
• w = 10 at 15° to the x-axis,

We resolve them into component form

So, u = -(ucos70°)i - (usin70°)j

u = -(0.3420u)i - (0.9397u)j

v = -(vcos47°)i + (vsin47°)j

v = -(0.6820v)i - (0.7314v)j

w = (wcos15°)i + (wsin15°)j

w = (0.9659w)i + (0.2588w)j

w = (9.659)i + (2.588)j

Since the sum of the three vectors is zero, we have that

u + v + w = 0

u + v = -w

So,

-(0.3420u)i - (0.9397u)j + [-(0.6820v)i - (0.7314v)j] = -[(9.659)i + (2.588)j]

-(0.3420u)i - (0.9397u)j -(0.6820v)i - (0.7314v)j = -(9.659)i - (2.588)j]

-(0.3420u)i -(0.6820v)i - (0.9397u)j - (0.7314v)j = -(9.659)i - (2.588)j]

-[0.3420u + 0.6820v]i - [0.9397u + 0.7314v]j = -(9.659)i - (2.588)j

Equating i components, we have

-[0.3420u + 0.6820v]i = -9.659i

0.3420u + 0.6820v = 9.659

Dividing through by 0.3420. we have

u + 1.994v = 28.242 (1) and

Also, equating j components, we have

- [0.9397u + 0.7314v]j = -2.588j

0.9397u + 0.7314v = 2.588  

Dividing through by 0.9397 we have

u + 0.778v = 2.754 (2)

a. The value of v

Subracring equation (2) from(1),we have

u + 1.994v = 28.242 (1)

-

u + 0.778v = 2.754 (2)

2.772v = 25.488

v = 25.488/2.772

v = 9.19

v ≅ 9.2

The value of v is 9.2

b. The value of u

Substituting v into (1), we have

u + 1.994v = 28.242 (1)

u + 1.994(9.19) = 28.242

u + 18.325 = 28.242

u = 28.242 - 18.325

u = 9.917

u ≅ 9.9

The value of u is 9.2

Learn more about vectors here:

brainly.com/question/25705666

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