Chapter Practicce
2 Marks Questions
1. Write a unit vector in the direction of the sum of vectors a =2i 2i+2j-5h and
b =2i +j-7k.
2. If a = 4i -j +k and b =2i -2j+X, then find a unit vector parallel to vector a+
3. If PO +0Q = Q0 +OR, then show that points P, Q and R are collinear.
4. Ifa 2i +2j+3h, b=-î+2+hand e 8i + jaresuchthat a +i
= =
bis perpendieularlar
to c then find the vlaue of A.
3 Marks Questions
5. Let a =i +j +h,b 4i -2 +3Xand c =i
= -
2j+k andfind avector ofmagnitude6
units which is parallel to the vector 2 a - b +3 c.
6: A vector r is inclined at equal angles to the three axes. Ifthe magnitude of r is
23 units, then find the value of r.
7. Ifa unit vector a makes anglewith i, with j and an acute angle6 with k, thenfind
3
the components of a and the angle 6.
8. Find the position vector of a point C which divides the line segment joining A and B
whose position vectors are 2 a+ b and a -3 6,externally in the ratio 1:2. Also, show
that A is the mid-point of the line segment BC.
9. Points L, M and N divide the sides BC, CA and AB of AABC in the ratio 1:4, 3:2 and
3:7, respectively. Prove that AL+BM+ CN is a vector parallel to CK, where k divides
AB in the ratio 1:3.
10. 1f a =2+i-3k and b=i-2j +h then find a vector of magnitude 5 units
perpendicular to both a and b.
11. Ifa =i +j+hand b =j -k, thenfind avector c,suchthat ax c =banda c=3
12. Using vectors, find the area oftriangle with vertices A(1,1,2), B(2,3,5) and C(1,5.5).
ectors
13. If a,b and c are three vectors, such that |al= 5,|bl=12 cl= 13 and a+ b+ c =0 then
find the value of a-b+b.c+c-a.
vectors
by the
14. The diagonals AC and BD of a parallelogram ABCD are represented
i+j-kand i - j +k, respectively. Find the area of the parallelogram.
4 Marks Questions
OX, OY and OZ.
15. Show that the vector i +j +k is equally inclined at axes
from right
=3i -2)+h, b =i-3j+5X andc =2j+j-4k
a
16. Show that the vectors a
angled triangle.
17. Prove that for any two vectors a and b, 1lal +bl slal +| 61
a +b c =0. Then prove that
18. If a, b and c are three vectors such that +
axb b xc = cxa.
5 Marks Questions
a. Prove that a, b and care
a, b and c are three vectorssuchthat ax6= c, bxc
=
19.
mutually at right angle and lbl 1,Iel la
= =
each other, then prove that
20. If a, b and c are perpendicular to
(a 6 x c = a'b'e.
to the opposite sides are
21. Prove that the perpendiculars from the vertices of a triangle
concurrent.
. b +- a2
22. In any AABC, prove by vector method, cos A=
2bc
Answers
26-3+2k 4. A=8
5. 21-4+ 4k 6.+2 +j+) 7. -and component of a =
10.+j+ k)
8. Position vector of c -33+56 3
12 13. -169 14. V2 sq units