Multiple choice questions Part.1 (please make sure that all the answers are correct )

1. An 855-Hz disturbance (wave) moves through an iron rail at a speed of 5130 m/s. What is the period of the wave?

0.0012 S

0.12 s

0.012 S

10.2 S

2. A wave has a frequency of 50 Hz and a wavelength of 10 m. What is the speed of the wave?

50 0 m

500 m/s

50 m/s

5 m/s

3. A mass on a spring vibrates in simple harmonic motion at an amplitude of 8.0 cm. If the mass of the object is 0.65 kg and the spring constant is 120 N/m, what is the frequency?

0.5 Hz

6 Hz

21 Hz

2.1 Hz

4. A wave has a wavelength of 10 m and a speed of 340 m/s. What is the frequency of the wave?

34 Hz

34 m/s

340 Hz

340 m/s

5. Suppose a spring is suspended with a mass of 4 kg at one end. The spring oscillates with a time period of 2 seconds. If a 6 kg mass is suspended from the same spring, what will be the time period?

2.45 seconds.

4.45 seconds.

6.45 seconds.

2.13 seconds.

6. A spring-mass system has a measured period of 8 seconds and a known mass of 15kg. Calculate the spring stiffness constant.

11.8 N/m

9.3 N/m

14.8 N/m

1.8 N/m

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Part.2

1. What is the net of all torques in the system shown?

+ 8.3 N m

- 8.3 Nm

+4.3 Nm

-4.3 Nm