A projectile is projected from the foot of an incline of angle 30 ◦ with a velocity 30 m/s. The angle
of projection as measured from the horizontal is 60 ◦. What would be its speed when the projectile
is parallel to the incline?
(a) 10 m=s (b) 2p3 m=s (c) 5p3 m=s (d) 10p3 m=s