Question

The angle which a vector i cap - j cap + ✓2 k cap makes with y-axis is:
a) 60°
b) 120°
c) 150°
d) tan-1 (-1/2)​

Answer 1

Answer:

R

=

i

+

j

+

2

k

Comparing the given vectro with R=R

x

i

+R

y

j

+R

z

k

R

x

=1, R

y

=1, R

z

=

2

and ∣

R

∣=

R

x

2

+R

y

2

+R

z

2

=2

cosα=

R

R

x

=

2

1

⇒α=60

o

cosβ=

R

R

y

=

2

1

⇒β=60

o

cosγ=

R

R

z

=

2

1

⇒γ=45

o