Mathematics MCQS for class 12 with Answers
Ifu=a1i + b1j +c1k & v =a2i +b2j + c2k be two non-zero vectors then u.v=
1
a1b1c1 + a2b2c2
a1a2 + b1b2 + c1c2
0
Two vectors are said to be equal, if they have _______ magnitude and ________ direction
Same, opposite
Same , same
Opposite, same
Opposite, opposite
Velocity, acceleration, force, weight are example of
Vectors
Both a and b
Unit vectors
Scalars
If cos ?,cos ? ,cos ? are direction cosines of a vector athen:
Cos?+Cos? +Cos?=0
Cos2 ? + Cos2 ? + Cos2 ? = 1
Cos? Cos?
Cos? + Cos? + Cos? = 1
For two vectors j& k, we have: j.k=
0
1
-1
2
For two vectors a&b :a.b=
a + b
a – b
ab
b.a
The dot product of unit vector k with unit vector k is
2
None of these
1
0
Moment of a force about a point is:
Vector quantity
None of these
Scalar quantity
zero
The dot product of unit vector j with unit of vector i is
3
2
1
0
2i x 2j . k =
2
3
0
4
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