Duration of one alif in tajweed

Q:

1. What is the duration of one alif in tajweed? How long should we stretch it?

2. I have seen in ‘simple rules of tajweed’ book that short madd duration is two alif. Can I stretch short madd for 3 Alif duration?

3. If sign of the short madd appears at the end of an ayat and we stop there, how long should the madd be stretched? I have heard in many tilawat that they stretch it for one alif when it appears at the end of ayat.

Shar'ee mile in kilometers

Q: Please explain how many kilometers are equal to 1 shar'ee meel (mile). It is mentioned in Beheshti Zewer under the ruling of tayammum. Generally in length; 1 mile = 1.6 km. Is there any diifernce between a shar'ee mile or and English mile? If yes please explain.