Q. A forced oscillator has a mass of 3 kg and is driven by a force of 12 N at a frequency of 2 Hz. What is the amplitude of the oscillation if the damping coefficient is 0.1 kg/s?
A.0.1 m
B.0.2 m
C.0.3 m
D.0.4 m
Solution
Using F = mAω², we find A = F / (mω²) = 12 / (3*(2π*2)²) ≈ 0.2 m.
Q. A mass attached to a spring oscillates with a damping coefficient of 0.3 kg/s. If the mass is 1 kg and the spring constant is 4 N/m, what is the damping ratio?
A.0.1
B.0.3
C.0.5
D.0.75
Solution
Damping ratio (ζ) = c / (2√(mk)) = 0.3 / (2√(1*4)) = 0.3 / 4 = 0.075.
Q. A mass-spring system is subjected to a periodic force. If the amplitude of oscillation is 0.1 m and the frequency is 2 Hz, what is the maximum velocity of the mass?
Q. A mass-spring system is subjected to a periodic force. If the amplitude of the forced oscillation is 0.1 m and the damping coefficient is 0.2 kg/s, what is the maximum velocity of the oscillation?
A.0.1 m/s
B.0.2 m/s
C.0.3 m/s
D.0.4 m/s
Solution
Maximum velocity (v_max) = Aω, where ω = 2πf. Assuming f = 1 Hz, v_max = 0.1 * 2π * 1 = 0.2 m/s.
Q. A mass-spring system oscillates with a frequency of 2 Hz. If the system is damped, what is the relationship between the damped frequency and the natural frequency?
A.Damped frequency is greater
B.Damped frequency is equal
C.Damped frequency is less
D.Damped frequency is unpredictable
Solution
In a damped system, the damped frequency is always less than the natural frequency.
Q. A mass-spring system oscillates with a natural frequency of 3 Hz. If a damping force is applied, what is the new frequency of oscillation if the damping ratio is 0.1?
A.2.8 Hz
B.2.9 Hz
C.3.0 Hz
D.3.1 Hz
Solution
New frequency (ω_d) = ω_n√(1-ζ²) = 3√(1-0.1²) ≈ 2.9 Hz.
Q. If a damped oscillator has a mass of 5 kg, a spring constant of 20 N/m, and a damping coefficient of 1 kg/s, what is the natural frequency of the system?
A.1 Hz
B.2 Hz
C.3 Hz
D.4 Hz
Solution
Natural frequency (ω_n) = √(k/m) = √(20/5) = √4 = 2 Hz.
Q. In a forced oscillation system, the driving frequency is 5 Hz and the natural frequency is 4 Hz. What is the ratio of the driving frequency to the natural frequency?
A.0.8
B.1
C.1.25
D.1.5
Solution
Ratio = driving frequency / natural frequency = 5 Hz / 4 Hz = 1.25.
Q. In a forced oscillation, if the amplitude is maximum, what can be said about the relationship between the driving frequency and the natural frequency?
A.Driving frequency is less
B.Driving frequency is equal
C.Driving frequency is greater
D.Driving frequency is unpredictable
Solution
Maximum amplitude occurs when the driving frequency is equal to the natural frequency.
Q. In a forced oscillation, the driving frequency is 2 Hz and the natural frequency of the system is 1.5 Hz. What is the ratio of the driving frequency to the natural frequency?
A.0.5
B.1
C.1.33
D.2
Solution
Ratio = driving frequency / natural frequency = 2 / 1.5 = 1.33