If a → , b → , c → are non-coplaner vectors such that b → × c → = a → ; c → × a → = b → ; a → × b → = c → , then which of the following is not TRUE?

| a → | = | b → | = | c → | = 2

| a → | | b → | | c → | = 1

Let α ∈ R and the three vectors a → = α i ^ + j ^ + 3 k ^ , b → = 2 i ^ + j ^ - α k ^ and c → = α i ^ - 2 j ^ + 3 k ^ . Then the set S = { α : a → , b → and c → are coplanar}

contains exactly two positive numbers

contains exactly two numbers only one of which is positive

EASY

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Which of the following is not a vector quantity?

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Important Questions on Motion in a Plane

MEDIUM

Physics>Mechanics>Motion in a Plane>Scalars and Vectors

Let

A, B, C, D

be the points with position vectors

3 \hat{i} - 2 \hat{j} - \hat{k}, 2 \hat{i} + 3 \hat{j} - 4 \hat{k}, - \hat{i} + 2 \hat{j} + 2 \hat{k}

and

4 \hat{i} + 5 \hat{j} + λ \hat{k}

respectively. If the points

A, B, C, D

lie on a plane, then the value of

λ

MEDIUM

Physics>Mechanics>Motion in a Plane>Scalars and Vectors

If vectors

a \hat{i} + \hat{j} + \hat{k}, \hat{i} + b \hat{j} + \hat{k}

and

\hat{i} + \hat{j} + c \hat{k} (a \neq b \neq c \neq 1)

are coplanar, then

\frac{1}{1 - a} + \frac{1}{1 - b} + \frac{1}{1 - c}

is equal to

HARD

Physics>Mechanics>Motion in a Plane>Scalars and Vectors

Let

S

be the set of all real values of

λ

such that a plane passing through the points

(- λ^{2}, 1, 1), (1, - λ^{2}, 1)

and

(1, 1, - λ^{2})

also passes through the point

(- 1, - 1, 1)

. Then

S

is equal to :

HARD

Physics>Mechanics>Motion in a Plane>Scalars and Vectors

\vec{a}, \vec{b}, \vec{c}

are non-coplaner vectors such that

\vec{b} \times \vec{c} = \vec{a}; \vec{c} \times \vec{a} = \vec{b}; \vec{a} \times \vec{b} = \vec{c}

, then which of the following is not TRUE?

EASY

Physics>Mechanics>Motion in a Plane>Scalars and Vectors

Vector

A

has a magnitude of

10

units and makes an angle of

30 °

with the positive x-axis. Vector

B

has a magnitude of

20

units and makes an angle of

30 °

with the negative x-axis. What is the magnitude of the resultant between these two vectors?

EASY

Physics>Mechanics>Motion in a Plane>Scalars and Vectors

Let

α \in R

and the three vectors

\vec{a} = α \hat{i} + \hat{j} + 3 \hat{k}, \vec{b} = 2 \hat{i} + \hat{j} - α \hat{k}

and

\vec{c} = α \hat{i} - 2 \hat{j} + 3 \hat{k} .

Then the set S = {

α : \vec{a}, \vec{b}

and

\vec{c}

are coplanar}

EASY

Physics>Mechanics>Motion in a Plane>Scalars and Vectors

The sum of the distinct real values of

μ

for which the vectors

μ \hat{i} + \hat{j} + \hat{k}, \hat{i} + μ \hat{j} + \hat{k}, \hat{i} + \hat{j} + μ \hat{k}

are co-planar, is

MEDIUM

Physics>Mechanics>Motion in a Plane>Scalars and Vectors

Let

\vec{a} = \hat{i} + \hat{j} + \hat{k}, \vec{b} = 2 \hat{i} + 2 \hat{j} + \hat{k}

and

\vec{c} = 5 \hat{i} + \hat{j} - \hat{k}

be three vectors. The area of the region formed by the set of points whose position vectors

\vec{r}

satisfy the equations

\vec{r} \cdot \vec{a} = 5

and

| \vec{r} - \vec{b} | + | \vec{r} - \vec{c} | = 4

is closest to the integer.

EASY

Physics>Mechanics>Motion in a Plane>Scalars and Vectors

A force $\vec{F} = 4 \hat{i} + 3 \hat{j} + 4 \hat{k}$ is applied on an intersection point of $x = 2$ plane and $x$ -axis. The magnitude of torque of this force about a point $(2, 3, 4)$ is ________.

(Round off to the Nearest Integer)

MEDIUM

Physics>Mechanics>Motion in a Plane>Scalars and Vectors

The unit vector perpendicular to the plane of

\vec{A} = \hat{i} - 3 \hat{j} - \hat{k}

and

\vec{B} = 2 \hat{i} + \hat{j} - \vec{k}

EASY

Physics>Mechanics>Motion in a Plane>Scalars and Vectors

The value of

m,

if the vectors

\hat{i} - \hat{j} - 6 \hat{k}, \hat{i} - 3 \hat{j} + 4 \hat{k}

and

2 \hat{i} - 5 \hat{j} + m \hat{k}

are coplanar, is

EASY

Physics>Mechanics>Motion in a Plane>Scalars and Vectors

The angle, between

\vec{A}

and the resultant of

2 \vec{A} + 3 \vec{B}

and

4 \vec{A} - 3 \vec{B}

MEDIUM

Physics>Mechanics>Motion in a Plane>Scalars and Vectors

If the vectors

\vec{α} = \hat{i} + a \hat{j} + a^{2} \hat{k}, \vec{β} = \hat{i} + b \hat{j} + b^{2} \hat{k}

and

\vec{γ} = \hat{i} + c \hat{j} + c^{2} \hat{k}

are three non-coplanar vectors and

|\begin{array}{l} a & a^{2} & 1 + a^{3} \\ b & b^{2} & 1 + b^{3} \\ c & c^{2} & 1 + c^{3} \end{array}| = 0,

then the value of

a b c

EASY

Physics>Mechanics>Motion in a Plane>Scalars and Vectors

\vec{a} = \hat{i} + \hat{j} + \hat{k}, \vec{b} = \hat{i} - \hat{j} + 2 \hat{k}

and

\vec{c} = x \hat{i} + (x - 2) \hat{j} - \hat{k}

and if the vector

\vec{c}

lies in the plane of vectors

\vec{a}

and

\vec{b},

then

x

equals

HARD

Physics>Mechanics>Motion in a Plane>Scalars and Vectors

The position vectors of the points

A, B, C

and

D

are

3 \hat{i} - 2 \hat{j} - \hat{k}, 2 \hat{i} - 3 \hat{j} + 2 \hat{k}, 5 \hat{i} - \hat{j} + 2 \hat{k}

and

4 \hat{i} - \hat{j} + λ \hat{k},

respectively. If the points

A, B, C

and

D

lie on a plane, the value of

λ

EASY

Physics>Mechanics>Motion in a Plane>Scalars and Vectors

If the vectors

a \hat{i} + \hat{j} + \hat{k}, \hat{i} + b \hat{j} + \hat{k}

and

\hat{i} + \hat{j} + c \hat{k}

are coplanar

(a \neq b \neq c \neq 1)

, then the value of

a b c - (a + b + c) =

HARD

Physics>Mechanics>Motion in a Plane>Scalars and Vectors

The unit vector which is orthogonal to the vector

\hat{i} + \hat{j} + \hat{k}

and is coplanar with vectors

\hat{i} + 2 \hat{j} - \hat{k}

and

2 \hat{i} + \hat{j} + 3 \hat{k},

EASY

Physics>Mechanics>Motion in a Plane>Scalars and Vectors

Let

\hat{i}

and

\hat{j}

be the unit vectors along

x

and

y

directions. Then the magnitude of

\hat{i} + \hat{j}

EASY

Physics>Mechanics>Motion in a Plane>Scalars and Vectors

The unit vector

(a \hat{i} + b \hat{j})

is perpendicular to

(\hat{i} + \hat{j}) .

The value of

b

can be:

EASY

Physics>Mechanics>Motion in a Plane>Scalars and Vectors

Force

\vec{F}

applied on a body is written as

\vec{F} = (\hat{n} \times \vec{F}) \cdot \hat{n} + \vec{G}

, where

\hat{n}

is a unit vector. The vector

\vec{G}

is equal to

Which of the following is not a vector quantity?

Important Questions on Motion in a Plane

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