A metal ball hangs on a string from a lab stand. Anselm lifts the ball to one side and lets go. The ball swings through the middle, out to the far side, and back again, over and over.
The same back-and-forth shows up all over physics, and this whole topic grows out of it. This lesson names the motion and the special position it swings about.
Watch where the ball would hang if Anselm never disturbed it: straight down, still, at the middle of the swing.
The position where the ball would sit still if left alone is called its rest position.
Pulled aside and released, the ball swings through the rest position to the far side, then back through it again.
The motion repeats: out, back, through the middle, out the other way, again and again.
One full trip counts as out to one side, back through the rest position, out to the other side, and back again.
Other things oscillate the same way. A flicked diving board tip moves up and down about its level rest position. A rocking chair tips forward and back about its balance position.
Beata sits on a playground swing, drifting forward and back through the lowest point of its arc. Is her motion an oscillation, and where is the rest position?
The swing repeats a back-and-forth motion.
The motion repeats about the lowest point of the arc, where the swing would hang still if left alone.
Yes: the motion is an oscillation, and the rest position is the lowest point, where the swing would hang still.
A diver bounces once off a diving board and swims away. The board tip keeps moving up and down about its level position for a few seconds. Name the board tip's rest position.
The rest position is where the tip would sit still if left alone.
Undisturbed, the board tip sits level.
The rest position is the board tip's level position. The tip oscillates up and down about it.
A metronome arm ticks left and right, over and over. Around which position does the arm oscillate?
Cosmo rides a skateboard across a half-pipe once, from one side to the other, and steps off at the far rim. Is the skateboard's motion an oscillation?
A wind chime tube swings back and forth after a gust, then slowly settles until it hangs still. Dilys says: 'The position where the tube finally hangs still is its rest position.' Is Dilys correct?
Which motion is an oscillation?
A bobblehead dog's head bobs forward and back after a tap. Which statement about the head's rest position is correct?
Which feature makes a motion an oscillation?