Transverse and longitudinal waves

Answer Key - Grade 11 Science Worksheet

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

1. 1.

   A seismograph records the S-wave 10 s after the P-wave. In this rock, P-waves travel 6.0 km/s and S-waves 3.5 km/s. How far away is the quake, Ari?

   84 km
2. 2.

   A seismograph records the S-wave 25 s after the P-wave. In this rock, P-waves travel 6.0 km/s and S-waves 3.5 km/s. How far away is the quake, Bo?

   210 km
3. 3.

   A seismograph records the S-wave 15 s after the P-wave. In this rock, P-waves travel 6.0 km/s and S-waves 3.5 km/s. How far away is the quake, Esme?

   126 km
4. 4.

   Jun shakes the same rope at twice the frequency, with the tension unchanged. What happens to the wave speed and the wavelength?

   • The speed doubles and the wavelength halves
   • The speed stays the same and the wavelength halves
   • The speed and the wavelength both halve
   • The speed doubles and the wavelength stays the same
5. 5.

   The tension in a rope is made 4 times as large. Wave speed goes with the square root of tension. The shaking frequency stays the same. What happens to the wavelength, Kira?

   • It halves
   • It doubles
   • It stays the same
   • It quadruples
6. 6.

   A wave passes from a light rope into a heavy rope. The frequency stays the same. What happens to the wavelength, Luz?

   • It gets longer, since a heavy rope carries waves farther
   • It gets shorter, since the frequency rises in the heavy rope
   • It gets shorter, since the wave travels more slowly on the heavy rope
   • It stays the same, since the same hand shakes both ropes
7. 7.

   A microphone records the pressure peaks (compressions) of a sound arriving every 2.5 ms. What is the frequency, Milo?

   • 40 Hz
   • 4,000 Hz
   • 400 Hz
   • 2.5 Hz
8. 8.

   That 400 Hz sound travels in 20 °C air at 343.3 m/s. What is its wavelength, Noah?

   • About 0.43 m
   • About 1.2 m
   • About 0.86 m
9. 9.

   A wave travels right along a rope. At one instant, point P is at the top of a crest. What is the velocity of P at that instant, Tala?

   • Zero: it is momentarily at rest at its highest point
   • Down, since it is about to fall
   • Right, at the speed of the wave
   • Up, since the point has just been lifted by the crest approaching it from the left
10. 10.

    As a wave passes, where is a point on the rope moving fastest, Zee?

    • At the rest position, passing through the middle
    • Everywhere the same, since the wave speed is constant
    • At the crest, where the rope is displaced furthest from its rest position
    • At the trough