On percussion: hammer blows, colliding balls, a wedge
Studies of impact - a hammer on a crossbow string, poppies cut by a knife, a wedge, and two balls of unequal speed
Headed 'De percussione' (On percussion), this leaf gathers Leonardo's studies of impact and the blow. He sketches a hammer striking the string of a crossbow and asks whether a blow lands with full force on an object that does not brace for it; nearby, poppies severed by a knife and the percussion of a wedge serve as further cases of a striking or cutting stroke. At the foot he poses a collision problem between two balls a and b moving at three and four degrees of velocity, asking how the impact differs if one ball is at rest or is moving to meet the other.
On this page
On percussion (heading)
The page opens with the title 'De percussione,' announcing a group of studies on percussion - the physics of the blow and of impact between bodies.
Hammer striking a crossbow string
A hammer is shown striking the string of a crossbow or an object held in balance. Leonardo asks whether the blow given upon an object that does not expect it is effective or not.
Poppies cut by a knife
Among the percussion cases he notes poppies severed by a knife, an example of a cutting stroke set beside the blows of hammer and wedge.
Percussion of a wedge
A further heading, without accompanying text, treats the percussion of a wedge, another instance of a driving blow.
Collision of two balls a and b
Two balls are labelled a and b: ball a moves with 3 degrees of velocity and ball b with 4 degrees. Leonardo asks what difference this impact has compared with the case where one ball stays still, or where it comes to meet the other with the said 4 degrees of velocity.