Unit 10 Review
Vibrations & Waves
Name:__________________________________
Date:_____________
Mod:_____________
Directions: Answer the following questions by writing in complete sentences when asked to describe or
explain. If the question asks you to solve, then show all work and circle your final answer with the
correct units.
1. Why does the formula for Hooke’s Law have a negative symbol? Explain using terms like the
restoring force and displacement.
2. a). A mass of 5kg hangs from a spring that has a spring constant of 30N/m. What is the
displacement of mass from the spring’s equilibrium position?
b). If the original spring was exchanged for a 20 N/m spring, what mass would be required to
hang from the spring in order to achieve the same vertical displacement?
3. A shock is pressed downward to a displacement of 20cm from its equilibrium with a force of
193N. What is the spring constant of the shock?
4. What is the term damping mean? Explain in terms of a car’s suspension system.
Unit 10 Review – Vibrations & Waves
Page 1 of 3
5. a). A person pushes in on a shock that has an uncompressed length of 0.35m and it compresses
to a length of 0.25m. If the spring constant of the shock is 1000N/m, how much energy is stored
in the shock?
b). If the person places a hammer on top of the shock, what will be the initial speed of the
launched hammer be if its mass is 0.75kg? (Hint: It’s launched vertically!)
6. Mr. Helm can swing back and forth two times over the course of 3.2 seconds. How long does it
take Mr. Helm to complete 1 full swing?
7. A spring inside of a jackhammer has a period of 0.025 seconds. What is the frequency?
8. Your TV sets at home usually have a frequency of 60Hz. This means that 60 frames of film are
appearing on the screen within one second. What is the period of the screens on the TV?
9. a). What is the period of a 75cm long pendulum?
b). What is the frequency of the pendulum?
Unit 10 Review – Vibrations & Waves
Page 2 of 3
10. A physicist wants to set the frequency of a pendulum to 0.2Hz. What length of string must the
physicist use in order to achieve this frequency?
11. What should the spring constant be if you want a 5kg mass to produce a period of 0.5 seconds?
12. a). A 3.705 kHz whistle produces sound waves that have a wavelength of 35.6 cm in water. Find
the speed of sound in the water.
b). The same whistle is used to produce the same frequency in air. If the speed of sound in air is
340m/s, what will the wavelength be?
13. I ray of light has a frequency of 450MHz. What is the wavelength?
14. What is the wavelength of an x-ray 3.1x1012 MHz?
15. What is the Doppler Effect?
Unit 10 Review – Vibrations & Waves
Page 3 of 3