Cosmo's lab sheet shows a bare snapshot of a rope wave and four jobs: mark the crests, mark the troughs, draw the amplitude, and bracket one wavelength.
Every label has already been coined. This lesson runs the routine that places all four on one picture, in an order that catches mistakes before they happen.
Start with the rest line. Find the dashed line of the undisturbed rope; every other label is measured against it.
Mark the crests: the highest points above the rest line.
Mark the troughs: the lowest points below the rest line.
Draw the amplitude arrow from the rest line up to one crest top. Never from a crest to a trough.
Bracket one wavelength between two successive identical points: one crest top to the next crest top, or one trough bottom to the next.
Check the pair of measures last: the amplitude runs vertically from the rest line; the wavelength runs horizontally along the wave.
Label a snapshot of a lake swell: the swell rises and dips evenly about a dashed line. Walk the five moves.
The dashed line of the calm lake is the rest line.
The highest points above it are the crests; the lowest points below it are the troughs.
The amplitude arrow runs from the rest line up to one crest top.
The wavelength bracket runs from one crest top to the next crest top.
The snapshot carries all four labels: crests, troughs, one amplitude arrow (rest line to crest), one wavelength bracket (crest to next crest).
Beata's wavelength bracket runs from one trough bottom to the next trough bottom. Does her bracket need redrawing?
A wavelength bracket needs two successive identical points.
Two successive trough bottoms are identical points.
No. Trough to next trough spans one wavelength, so her bracket stands.
A snapshot of a rope wave marks three points: J at a highest point, K at a lowest point, and L on the rest line. Which letter belongs under the label crest?
A snapshot carries three drawn arrows: J from the rest line up to a crest top, K from a crest top down to the next trough bottom, and L from one crest top across to the next crest top. Which arrow is a correctly drawn amplitude?
Dilys brackets the distance from one trough bottom to the next trough bottom and labels it one wavelength. Is her label correct?
A labeled snapshot marks four points: M at a highest point, N on the rest line, P at a lowest point, and Q halfway down a dip. Which letter belongs under the label trough?
Four brackets are drawn on one snapshot: J from a crest top to the next crest top, K from a crest top to the very next trough bottom, L from a rest-line crossing to the next crest top, and M from the rest line up to a crest top. Which bracket spans one wavelength?
On a snapshot, the vertical distance from a trough bottom to a crest top measures 14 cm. Enter the length, in cm, of a correctly drawn amplitude arrow from the rest line to the crest top.