## Unit 10

1. A pulse travels along a 2.5 meter spring as shown below. It travels down and back in 10 seconds. Determine the speed of the pulse.

.5 m/s

Refer to the wave below to answer questions 2 - 4.

2. The above wave is a(n): (b) Transverse Wave

a. Longitudinal Wave.

b. Transverse Wave.

c. Converse Wave.

d. Psychotic Wave.

3. The wavelength of the wave is: (a) 2 meters

a. 2 meters b. 4 meters c. 6 meters d. 8 meters

4. If the frequency of the above wave is 10 Hz, determine the speed of the wave.

v=(2m)(10Hz)=20m/s

5. A bird notices that 10 waves pass her in 20 seconds. She also estimates the distance between crests of waves to be 4 meters. Determine the speed of the waves.

v=(4m)(10/20s)=2m/s

Refer to the standing wave below to answer questions 6 - 8.

6. Determine the number of waves present. Explain.

There is one wave present. Each loop is just half of a wave.

7. Determine the wavelength.

4 m

8. If the speed of the wave is 30 m/s, determine the frequency.

9. Draw in the superposition of the two waves when they pass point X below.

Your picture should have the wave on the right with a small bump on top of it the size of the left wave. ???????

Refer to the wave traveling from a more dense medium into a less dense medium shown below for questions 10 - 12.

10. Determine the frequency of the wave in medium A.

11. As the wave is transferred into medium B, what will be its frequency?

6Hz. Frequency is constant.

12. Determine the wavelenth of the wave as it travels through medium B.

13. Mr. Wegley's daughter Corine, while playing with a slinky tied to a string which is in turn held by Corine's younger brother Robert. She shakes it 12 times in 6 seconds and creates a wave that is 1 meter long in the slinky.

a. Determine the speed of the wave while it is in the slinky.

b. Determine the frequency of the wave once it travels from the spring

2Hz. Frequency is constant.

A pulse is sent from a more rigid medium toward a less rigid medium as shown below. Use this situation to complete 14 - 18.

14. As the pulse meets the boundary, part of the wave will be transmitted and part will be reflected. Sketch in these two pulse on the media shown below.

You should have a wave on each side with smaller amplitude than the original wave. Neither of them should be inverted.

15. Will the reflected pulse's frequency change with respect to the initial pulse? Explain.

No, frequency is always constant.

16. Will the reflected pulse's wavelength change with respect to the initial pulse? Explain.

No. f=(velocity)(wavelength). Since frequency and velocity stay the same, so must wavelength.

17. Will the reflected pulse's speed change with respect to the initial pulse? Explain.

No, the reflected wave will still be travelling in the same medium so its speed will also stay the same.

18. The transmitted pulse's __frequency__ will remain constant.

A pulse is sent from a less rigid medium toward a more rigid medium as shown below. Use this situation to complete 19 - 22.

19. As the pulse meets the boundary, part of the wave will be transmitted and part will be reflected. Sketch in these two pulse on the media shown below.

You should have waves on each side once again with amplitudes smaller than the original wave. However, the wave on the left should be inverted.

20. Will the reflected pulse's frequency change with respect to the initial pulse? Explain.

No, frequency is always constant.

21. Will the reflected pulse's wavelength change with respect to the initial pulse? Explain.

No. The frequency and velocity still remain the same so the wavelength must also.

22. Will the reflected pulse's speed change with respect to the initial pulse? Explain.

No, the reflected wave will still be travelling in the same medium.

23. The speed in the less rigid medium is 5 m/s while the speed in the more rigid medium is 3 m/s. An original wave is created by Hanna Wavin's hand as she holds the less rigid rope and shakes it 10 times in 4 seconds.

a. Determine the frequency of the wave Hanna creates in the less dense medium.

b. Determine the frequency of the wave transmitted into the more dense medium.

2.5 Hz

c. Determine the wavelength of the transmitted wave.

d. In which medium is the wavelength largest? Explain.

In the less rigid medium. Wavelength is directly related to velocity and frequency is always constant. Therefore, the medium with a higher velocity will have a higher wavelength.

Glenbrook South Physics Team - Tom Henderson, John Lewis, Neil Schmidgall, Dave Smith, Suzanne Webb & Brian Wegley
4000 West Lake Ave
Glenview, IL 60025 - 1200
(847)729-2000
Page Maintained by: Brian Wegley

Last Updated: October 8, 1997