vectors

The value of (i-j).(2i-j+k) is:

• -3

• +3

• 0

• 2

If the dot product of two vectors is 0 then the angle between them (in degrees) will be:

• 0

• 180

• 60

• 90

The magnitude of vector i-j-k is

• -1

• +1

•  $\sqrt{3}$  

• none of these

The angle betweeen the vectors (i+j) and (-i+j) (in degrees) is:

• 0

• 45

• 90

• 180

The value of x, so that xi+0.4j+0.8k is a unit vector is:

• 1

• $\sqrt{2}$

• -0.2

• $\sqrt{0.2}$

A vector when added to 2i-j+k and -i-j+k gives null vector. The vector is:

• i-2j+2k

• -i+2j-2k

• 2i-2j+2k

• 2i-j+2k

Choose the incorrect option:

• $\overrightarrow{A}$ . $\overrightarrow{B}$ = $\overrightarrow{B}$ . $\overrightarrow{A}$

• i.j=0

• k.k=0

• j.j=1

The angle between two equal vectors so that there resultant is equal in magnitude of either,will be:

• 45⁰

• 60⁰

• 90⁰

• 120⁰

If two numerically equal vectors P and Q acting at a point produce a resultant vector of magnitude P then the angle between the two original vectors is ?

• 90 ⁰

• 120⁰

• 0⁰

• 45⁰

A particle of mass m is projected with a velocity v making an angle 45⁰ with the horizontal. When the particle lands on the ground the magnitude of the change in its momentum will be: ___________

• 2 mv

• mv / √2

• mv √2

• zero