Initial vs. Final velocity of projectile with no net displacement

[PhysicsAdvice]

if a ball is thrown and caught at the same height with constant horizontal velocity and no vertical displacement is its initial and final velocity the same?

since v2y^2=v1y^2+2aDy, no displacement means final vertical velocity will be the same as initial,

since v2x=v1x, horizontal velocity will be the same, so v2=v1

 

[SammyS]

Velocity is a vector quantity.

The direction of the ball when it is caught is different from when it is thrown.

 

[PhysicsAdvice]

right, so at first it would be in one direction then a different direction but does the value change other than that?

 

[SammyS]

The magnitude of the velocity (which is the speed) will be the same. The velocity, however, will be different because the vertical component of velocity will have changed sign.

 

[xiaoB]

if a ball is thrown and caught at the same height with constant horizontal velocity and no vertical displacement is its initial and final velocity the same?

since v2y^2=v1y^2+2aDy, no displacement means final vertical velocity will be the same as initial,

since v2x=v1x, horizontal velocity will be the same, so v2=v1

Yup ! It would be the same but you can't using the vertical displacement equation to prove the horizontal velocity.