EIT Dynamics and Vibrations 4

Question 1

A spring-mass system has k = 400 N/m and m = 4 kg. What is the natural frequency in Hz?

Accepted Answer

1.59 Hz

Answer

0.79 Hz

Answer

3.18 Hz

Answer

10.0 Hz

Question 2

A simple pendulum has a length of 1 m. What is its period of oscillation? (g = 9.81 m/s²)

Accepted Answer

2.0 s

Answer

0.5 s

Answer

1.0 s

Answer

4.0 s

Question 3

Springs k₁ = 100 N/m and k₂ = 200 N/m are connected in series. What is the equivalent stiffness?

Accepted Answer

66.7 N/m

Answer

50.0 N/m

Answer

150.0 N/m

Answer

300.0 N/m

Question 4

Springs k₁ = 150 N/m and k₂ = 250 N/m are connected in parallel. What is the equivalent stiffness?

Accepted Answer

400 N/m

Answer

93.75 N/m

Answer

200 N/m

Answer

250 N/m

Question 5

What is the critical damping coefficient for a system with m = 2 kg and k = 200 N/m?

Accepted Answer

40 N·s/m

Answer

10 N·s/m

Answer

20 N·s/m

Answer

80 N·s/m

Question 6

In a free vibration test, successive amplitudes are 5 mm and 2.5 mm. What is the logarithmic decrement?

Accepted Answer

0.693

Answer

0.347

Answer

0.500

Answer

2.000

Question 7

An underdamped spring-mass system is given an initial displacement and released. Which response best describes the subsequent motion?

Accepted Answer

Oscillation with exponentially decreasing amplitude

Answer

Exponential decay without oscillation

Answer

Constant-amplitude oscillation indefinitely

Answer

Linearly growing oscillation