What is acceleration in tennis and velocity?

[jrock_kpop]

im really confused between the difference..help?

 

[Danger]

Tennis and velocity are not even vaguely within the same linguistic paradigm, so I'm a bit confused.
If, by chance, you refer to the difference between acceleration and velocity in regard to the game of tennis, then you might just as well forget about tennis altogether. No matter what physical activity is taking place, the answer will be the same.
To start with, speed is a scalar measurement. It has only one component.
Velocity is a vector measurement, in that it incorporates both speed and direction.
For example, 100 km/h is a speed. 100 km/h due east is a velocity.
Acceleration is a measurement of the change in speed and/or direction; hence a change of velocity.
Some objects, such as a tennis ball in your case, or a baseball, or a cueball (in my realm) can undergo an acceleration even after leaving the initial launching point by transferring spin to the environment. That's how you get weird tennis shots, curve balls, or masses in pool.

edit: Oops! I just now noticed that this was your first post. Had I realized it earlier, the opening sentence of my reply would have been "Welcome to PF, Jrock." Oh, well... I guess that it's never too late. So—welcome aboard, mate.

 

[mishrashubham]

I am no expert at tennis but I think this will give you more insight.

http://tt.tennis-warehouse.com/showthread.php?t=351971