Before learning to jump balls, you should be able to:
- make 85 degree angle cuts better than 90% of the time
- draw the ball the length of the table
- use force follow to bounce of a single rail twice
- occasionally run 8 balls in a row
- miscue less than once a night
- 'feel' the difference between blue and green chalk
Learn the above before even beginning to learn to jump.
Now given that you can perform the above: the 'trick' to the jump shot is the release of pressure on the cue at the moment of impact. Note, this is not a slowing of the cue stick at impact, but releasing your grip so that as the tip and shaft deflects away from the cue ball, the rest of the cue obeys this deflection and allows the cue (tip) to get out of the way. You don't need "that much" force at impact, and you do have to hit the cue ball within a 1/2 tip of a line from the center of the cue ball to the center of the tip. That is: the target on the cue ball is about the size of a pencil eraser.
It is very much more like throwing a dart where the release point is the instant of impact of the tip with the cue ball, than any other stroke (other than a serious massé). Because of these effects, having a stick weighting less than 12 oz helps the learning process immensely--and this is why jump sticks were invented.
If you hit the cue ball father off center than described above the cue ball will not jump--the stick will hold the cue ball on the table and it won't jump.
If the cue stick is not free floating in air at impact it is difficult for the cue-ball to leave the table.
All this physics plays out in on-the-order-of 1-2 milliseconds, far faster than a human muscle can react.