# Farm Tractor Questions and Answers – Operator Exposure to Vibration and Control

This set of Farm Tractor Multiple Choice Questions & Answers (MCQs) focuses on “Operator Exposure to Vibration and Control”.

1. What is meant by frequency in a tractor operation?
a) f = 1/T
b) f = T
c) f = 1 – T
d) f = T – 1

Explanation: Frequency is the number of occurrences/cycles in a specific period of time. It is a measure of vibration. It is measured in Hertz (Hz). F = 1/T, where T is the duration for the completion of one cycle. Here it is the frequency of the tractor parts like operator seat etc.

2. Prolonged exposure to vibrations causes fatigue to the operator.
a) False
b) True

Explanation: The vibrations caused by the tractor will increase the strain in the operator and so it will cause fatigue to the operator. Tractors should be designed to have minimum vibrations.

3. Operator seat of a tractor is subjected to which type of vibration?
a) Forced vibration
b) Free vibration
c) Damped vibration
d) Applied vibration

Explanation: Tractor operator seat is subjected to forced vibration as it receives vibrational force from the chassis – an external source. Vibrations with higher frequency are not suitable for the operator.

4. Calculate the tractor chassis frequency in rad/s of a tractor having frequency 25 Hz.

Explanation: ωt = 2πf
Where ωt is the tractor chassis frequency in rad/s
ωt = 2 * π * 25

5. Find the frequency in hertz if the number of occurrences is 1800 in a period of one minute.
a) 30 Hz
b) 29 Hz
c) 31 Hz
d) 32 HZ

Explanation: f = 1/T     (where T is in seconds)
Where 1 is the number of occurrence in the formula similarly the number of occurrences given is 1800.
= 1800/60
= 30 Hz

6. Find the damped frequency of a tractor seat given the natural frequency is 20 Hz and the damping ratio is 0.5.
a) 15 Hz
b) 16 Hz
c) 17 Hz
d) 18 Hz

Explanation: ωd = ωn√(1-ζ2)
Where ωd – damped frequency, ζ – damping ratio and ωn – natural frequency
= 20 √(1-0.52)
= 17.32

7. Find the damping ratio given the seat suspension damping rate is 500 N/ms, the mass of the tractor seat + operator is 80 kg and the natural frequency is 20 rad/s.
a) 0.10
b) 0.15
c) 0.18
d) 0.20

Explanation: Damping ratio = C/Cc
Where C – seat suspension damping rate
Cc – Critical damping rate
Cc = 2 M ωn
Where M – the mass of the tractor seat and operator, ωn – undamped natural frequency
ζ = 500 / 2 * 80 * 20 = 0.15

8. Damping ratio has no unit.
a) True
b) False

Explanation: Damping ratio has no unit as it measures the damping in the system. Here the damping refers to the reduction in the vibration/oscillation. It is also referred to as the damping factor.

9. Find the vibration acceleration level given RMS value of vibration acceleration is 2 m/s2.
a) 7 dB
b) 6 dB
c) 8 dB
d) 9 dB

Explanation: Vibration acceleration level = 20 log10 (VRMS / V0)
Where V0 is the reference vibration acceleration (1 m/s2)
= 20 log10 (2/1) = 6.02 dB

10. Find the RMS value of vibration acceleration given that the peak vibration acceleration is 10 m/s2.
a) 7.07 m/s2
b) 7.5 m/s2
c) 8.07 m/s2
d) 9.07 m/s2

Explanation: VRMS = (1/√2) * (Vpeak)
= (1/√2) * (10)
= 7.07 m/s2
Where Vpeak – peak vibration acceleration, VRMS – root mean square (RMS) value of vibration acceleration.

Sanfoundry Global Education & Learning Series – Farm Tractor.

To practice all areas of Farm Tractor, here is complete set of Multiple Choice Questions and Answers.

If you find a mistake in question / option / answer, kindly take a screenshot and email to [email protected]

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