Meaning of keel over

1. The old man suddenly keeled over while walking down the street.
2. After running a marathon, I felt like I was going to keel over from exhaustion.
3. The boat keeled over in the strong winds, causing everyone to panic.
4. The tree keeled over after being struck by lightning.
5. As soon as the teacher fainted, the students watched her keel over in shock.
6. The weight of the heavy load caused the truck to keel over on the sharp turn.
7. The horse suddenly keeled over while trotting in the field.
8. The drunk man stumbled and keeled over on the sidewalk.
9. The tower of blocks keeled over when the child bumped into it.
10. The athlete felt dizzy and thought he might keel over during the intense workout.