Ch-3

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Ch-3

• Help-Session

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CH-3-072

• T072 Q5.Vectors a, b, and c are related through
  equations and ABC A-B5C. If C 3i4j, what
  is the magnitude of vector a ? (Ans 15)

• Q6. Three vectors F,v and B are related through
  F 5(vxB) . If vector v3i -5j and B-2k, then
  vector F is (Ans 50 i30 j )

ABC A-B5C Adding both equations together
2A6C A3C A3C9i12j ?A ? ?(92122) 15
F 5(vxB)5(3i -5j)x(-2k) 5 -6i
xk10jxk)56j10i 30 j50 i
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CH-3-072

• Q7. A vector A of magnitude 20 is added to a
  vector B of magnitude 25. The magnitude of the
  vector AB can be (Ans 12)

Q8. Vectors F and G are defined as F3i4j , and
G-ij . Find the component (projection) of
vector G along the direction of vector F .( Ans
0.20)
F.G?F??G?cos ? FxGxFyGy ?G?cos ?
(FxGxFyGy)/?F? (-34)/?(3242)1/5 0.2
?AB?max 252045 ?AB?min 25-20 5 Value of
?AB?5-45
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CH-3-071
T071  In Fig. 3, the unknown vector C is given
by (AnsB-A )
Q8. Two vectors are given by
P-1.5i2j,and Q1.0j . The angle that the
vector makes with the positive x-axis is (A
135)
A-C B -CB-A CA-B
?cos-1(PxQxPyQy)/?P ? ? Q ? cos-1(2x1)/(??1.
5222) x1)
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CH-3-071
Q5. Q9. A man walks 5.0 km due North, then 13 km
22.6 South of East, and then 12 km due West. The
man is finally at (Ans where he started)
Add components A5j B13 km 22.6 degrees south
of east C -12i Resultant must be Zero