PSC 1121 Lecture 5: Physical Science Independence of Motions (L5)
Document Summary
Here t(cid:449)o hea(cid:448)y (cid:271)alls (cid:271)egi(cid:374) to (cid:862)free fall(cid:863) at the sa(cid:373)e ti(cid:373)e. the red o(cid:374)e is dropped, so it (cid:373)o(cid:448)es straight downward. The horizontal line show that they keep pace with each other in the vertical direction. They have the same acceleration, g, downward, and they both started with zero speed in the downward direction: the horizo(cid:374)tal (cid:448)elo(cid:272)ity does(cid:374)"t (cid:272)ha(cid:374)ge a(cid:374)d re(cid:373)ai(cid:374)s the sa(cid:373)e. The yello(cid:449) (cid:271)all"s horizontal speed is not affected by gravity, which acts only in the vertical direction. Cannonballs shot horizontally with different speeds from the ship travel difference distances. But each cannonball drops the same distance in the same amount of time, since vertical acceleration is the same for each. The cannonball initially has the horizontal speed of the plane. Neglecting air resistance, it keeps that horizontal speed as it falls so it stays beneath the airplane. In the movie speed, a bus had to maintain a constant speed otherwise a bomb would have exploded.
