Transverse and longitudinal waves

Answer Key - Grade 11 Science Worksheet - Challenge Me

Circle the best answer, or write your answer on the line.

1. 1.

   A point on a rope moves up and down with amplitude 2 cm at 4 Hz. Its greatest speed is 2πfA. What is it, to the nearest 0.1 cm/s, Ari?

   50.3 cm/s
2. 2.

   A point on a rope moves up and down with amplitude 1.5 cm at 2 Hz. Its greatest speed is 2πfA. What is it, to the nearest 0.1 cm/s, Bo?

   18.8 cm/s

3. Read this first

   Seismograph readings (example data)

   Station	Distance (km)	P arrives (s)	S arrives (s)
   A	84	14	24
   B	168	28	48
   C	252	42	72

4. 3.

   What does the table show about the gap between the S and P arrivals, Jun?

   • The gap shrinks with distance, since the S-wave catches up
   • The gap grows in step with distance: 10 s, 20 s and 30 s at 84, 168 and 252 km
   • The gap stays the same at each station, since both waves start together and travel together
   • The gap grows faster than the distance: it triples while the distance doubles
5. 4.

   A station not in the table records the P-wave at 21 s after the quake. When should the S-wave arrive, Kira?

   • 27 s
   • 42 s
   • 36 s
   • 31 s
6. 5.

   Station D is 336 km from the quake. How many seconds after the P-wave does the S-wave arrive, Luz?

   • 40 s
   • 96 s
   • 16 s
   • 56 s
7. 6.

   Milo says a slinky shaken sideways makes a longitudinal wave, since a slinky is a spring. Agree or disagree?

   • Disagree: shaking sideways makes a transverse wave; the direction of motion decides the type
   • Agree: sideways shaking squeezes the coils along the slinky, which is a longitudinal motion
   • Disagree: a slinky makes transverse waves, whichever way it is shaken
   • Agree: a spring makes longitudinal waves, whichever way it is shaken
8. 7.

   A cork on a deep-water wave moves in a small circle: up and forward, then down and back. Noah says water waves are purely transverse. Agree or disagree?

   • Agree: the cork goes up and down as the wave passes, so the wave is transverse
   • Disagree: the circle has a part along the wave as well as up and down, so the wave is a mix
   • Disagree: the cork moves just along the wave, so the wave is longitudinal in the usual sense of the word
   • Agree: a circle is made of two sideways motions, so the wave must be transverse
9. 8.

   Which pair are both transverse mechanical waves, Ren?

   • Sound in air and an earthquake P-wave on its way through the crust
   • A shaken rope and an earthquake S-wave
   • Radio waves and sound in air
   • Light and a shaken rope
10. 9.

    A graph of one rope point's displacement against time repeats every 0.50 s. The wavelength is 0.90 m. How fast does the wave travel, Tala?

    • 2.0 m/s
    • 0.45 m/s
    • 0.56 m/s
    • 1.8 m/s
11. 10.

    In steel, longitudinal waves travel at about 5,900 m/s and transverse waves at about 3,200 m/s. A strike sends both along 6.0 m. How much later does the transverse wave arrive, Zee?

    • About 1.0 ms
    • About 1.9 ms
    • About 2.9 ms
    • About 0.86 ms