Question

Two equal velocities have resultant equal to
either of the two. The angle between
their directions is
a. 60
b. 90
Col20
d. 180°​

Answer 1

Explanation:

R

2

=P

2

+Q

2

+2PQcosα

P

2

=P

2

+P

2

+2PPcosα

=2P

2

+2P

2

cosα

=2P

2

(1+cosα)

1+cosα=

2

1

⇒2cos

2

2

α

=

2

1

⇒cos

2

2

α

=

4

1

⇒cos

2

α

=

2

1

=cos60

o

⇒

2

α

=60

o

⇒α=120

o