Ideal mechanical advantage correlates directly with velocity ratio.
3.
If both the friction and ideal mechanical advantage are high enough, it will self-lock.
4.
The ideal mechanical advantage of the block and tackle is equal to the number of parts of the rope that support the moving block.
5.
Whether a machine is self-locking depends on both the friction forces ( coefficient of static friction ) between its parts, and the distance ratio " d in / d out " ( ideal mechanical advantage ).