1. | vector \((A\times B)\times C\) is not zero unless vectors \(B\) and \(C\) are parallel. |
2. | vector \((A\times B).C\) is not zero unless vectors \(B\) and \(C\) are parallel. |
3. | if vectors \(A,B\) and \(C\) define a plane, \((A\times B)\times C\) is in that plane. |
4. | \((A\times B). C= |A||B||C|\rightarrow C^2= A^2+B^2\) |
The incorrect statement/s is/are:
1. (b), (d)
2. (a), (c)
3. (b), (c), (d)
4. (a), (b)
(1) Hint: The resultant of three vectors will be equal to zero only if the vectors are coplanar.
Step 1: Find if the vectors are coplanar.
Given, A + B + C = 0
Hence, we can say that A, B, and C are in one plane and are represented by the three sides of a triangle taken in one order.
Step 2: Find the incorrect statements one by one.
It cannot be zero as
If B and C are not parallel, then (AxB) will be perpendicular to the plane of A, B and C.
Hence, (AxB).C = 0 whatever be the situation is. Hence, statement (b) is incorrect and option.
Also, (AxB)xC will be in the plane of A, B and C and statement (c) is correct.
Statement (d) is also incorrect as discussed already.
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