The force is felt alike by both bodies; thus, when one head is struck against another, both are equally hurt.
Do bodies, when moving rapidly, strike with more force than when moving slowly?
Yes; the force with which they strike depends upon their velocity.
What examples of this force may be given?
A nail may be driven into a board by a hammer, when it falls rapidly upon the nail; a bullet may be shot through a plank; and even a tallow candle, when shot from a gun, may move with velocity enough to pass through a pine board.
Why do large bodies start slowly?
Because it takes some time for the force to reach all parts of them.
Why is it difficult for horses to start a loaded wagon?
Because they must pull some time before the force reaches all parts of the wagon, causing it to move.
Why is machinery slow at starting?