Which of the following is an example of the Doppler effect?
Vibrations from a tuning fork pass through the air and cause a nearby dish of
water to produce ripples of the same frequency.
Two identical musical instruments being played next to each other will produce a
sound twice as loud as if only one were played.
A hiker shouts "hello" into a canyon and hears it repeated back several times
before it fades away.
The siren of a police car sounds different when the car is coming toward you
than it does when it passes you.

Which of the following correctly describes the early view of catastrophism?

An alligator swims to the left with a constant velocity of 5 \,\dfrac{\text{m}}{\text s}5 s m ? 5, space, start fraction, m, divided by, s, end fraction. when the alligator sees a bird straight ahead, the alligator speeds up with a constant acceleration of 3 \,\dfrac{\text {m}}{\text s^2}3 s 2 m ? 3, space, start fraction, m, divided by, s, start superscript, 2, end superscript, end fraction leftward until it reaches a final velocity of 35 \,\dfrac{\text {m}}{\text s}35 s m ? 35, space, start fraction, m, divided by, s, end fraction leftward. how many seconds does it take the alligator to speed up from 5 \,\dfrac{\text {m}}{\text s}5 s m ? 5, space, start fraction, m, divided by, s, end fraction to 35 \,\dfrac{\text {m}}{\text s}35 s m ? 35, space, start fraction, m, divided by, s, end fraction?

If the chemical properties of a substance remain unchanged and appearance or shape of a substance changes it is called a ?