# A projectile is fired with a speed u at an angle #theta# with the horizontal. Its speed when its direction of motion makes an angle #alpha# with the horizontal is?

##
A: #usecthetasecalpha#

B: #usecthetasinalpha#

C: #ucosthetasecalpha#

D: #usinthetasecalpha#

PLEASE EXPLAIN EACH AND EVERY STEP

A:

B:

C:

D:

PLEASE EXPLAIN EACH AND EVERY STEP

##### 1 Answer

Let the velocity of projection of the object be **u** with angle of projection

The vertical component of the velocity of projection is

Now if **t** be the time after the projection of the projectile, its direction of velocity makes angle

The vertical component of the velocity after time

But the horizontal component remains unaltered as

So

So option C is accepted