4 by 5 Tri-X film
Model 553 Multiflash Units
20 flashes per second
1.0 millisecond exposure per flash
High speed multiple-image photographs were made useful as a data base from which we could extract otherwise unseen events for analysis.
According to Newton's theory, the second law states that the force of gravity accelerates a body in the direction it is already moving, and so speeds it up uniformly at the rate 32 feet per second squared. Acceleration, change in velocity as a function of gravity, is apparent in the case of the hammer.