ClipArt ETC
"The ball C is placed on a square frame between two upright wires, on each of which a ball slides so as to strike C when it descends. Let the ball A drop, and it will drive C to D... Let the ball B drop, and it will drive C to E; this is simple motion. Let A and B drop at the same instant, and they will drive C to F; this is resultant motion." —Quackenbos 1859

Resultant Motion with Ball

"The ball C is placed on a square frame between two upright wires, on each of which a ball slides so…

"We have an example of resultant motion in a boat which a person attempts to row north across a river, while the tide carries it to the east. Each force produces the same effect as if acted alone; and the boatman, when he has crossed the river, will find himself neither due north nor due east of the point from which he started, but northeast of it." —Quackenbos 1859

Resultant Motion with Boat

"We have an example of resultant motion in a boat which a person attempts to row north across a river,…

"Let, for instance, the force used by the boatman be twice as great as that of the tide. Then by the time he would reach B, the tide would have carried his boat one-half of that distance, to D." —Quackenbos 1859

Resultant Motion with Boat

"Let, for instance, the force used by the boatman be twice as great as that of the tide. Then by the…