Take the 2-minute tour ×  Obviously, you touch the screen and
they turn around. But can someone explain the physics behind
them? How do I know how much room it takes to turn around? What
direction do they go once turned around?  share|improve this
question add comment  1 Answer  The time it takes for a
boomerang bird to turn around appears to be based directly on
its momentum. If you shoot straight up and trigger it at the
apex of its flight, it should change direction immediately
because it has no momentum. On the opposite end of the spectrum
is when you trigger it after it's been falling downward for a
second -- its direction will barely be altered before it hits
the ground since its momentum is high.  The boomerang bird is
accelerated directly left if shot to the right, and directly
right if shot to the left. Its up/down momentum and acceleration
are not altered. So if it has no up/down momentum, it will fly
directly left/right after the trigger plus the effect of gravity
(so it will start out directly lef