Question

A particle is fixed velocity of u making angle teta with an horizontal what is the change in velocity when is at in highest point​

Answer 1

A particle is projected upwards at an angle of $\theta$ with the horizontal with the velocity of u .

Wheneverthat object reaches the highest point the y-axis component of velocity becomes zero because of gravity; where as the x-axis component remains constant. So velocity change doesn't take place along the x-axis simply because there is no acceleration component along the x axis.

So the main change in velocity occurs in the y component.

Initial Y axis velocity = $u\cos{\theta}$

Final Y axis velocity at highest point = 0

So change in velocity will be :

$\boxed{\huge{\red{\bold{ \Delta v = -u\cos{\theta}}}}}$

Answer 2

A particle is projected upwards at an angle of  with the horizontal with the velocity of u .

Wheneverthat object reaches the highest point the y-axis component of velocity becomes zero because of gravity; where as the x-axis component remains constant. So velocity change doesn't take place along the x-axis simply because there is no acceleration component along the x axis.

So the main change in velocity occurs in the y component.

Initial Y axis velocity =  u cos theta

Final Y axis velocity at highest point = 0

So change in velocity will be :