MBA camera or iPhone camera for analysing tennis shots in slow motion? I want to practise tennis shots and see how I am doing. I want to use the MBA camera in my laptop or iPhone for this. How can I do it? Some apps for this purpose?

Please keep the focus on Apple products, photography-oriented answers here.
The MBA build in cameras wont do high rate frames per second needed for your purpose.

They are a web camera type and the CCD/CMOS chip is not of a kind that can do that, regardless of the software.

iSight is a webcam, with video capture at 30 frames per second in 24-bit color.

On the iPhone there is a chance since it has an improved camera:

The iPhone 5s has a 120-frames-per-second slow-motion video mode and precision autofocus matrix metering. 

Sport events would use 300 FPS on a professional level with high resolution.