Rajasthan PSC — Assistant Agriculture Engineer (Agriculture Engineering syllabus) · India · Rajasthan Public Service Commission
Original practice questions written to the published syllabus · not past papersHow soil resists tools and supports wheels: draft, slip, tractive efficiency, weight transfer and stability.
In the exams: GATE AG Section 3 (traction asked in all 8 papers 2019–26; weight transfer and stability in 5 of 8); ICAR AICE subject 39 Unit 6; ASRB NET FMP
Rajasthan PSC — Assistant Agriculture Engineer
Traction and CG determination named in the farm power syllabus; direct formula questions.
How our questions for Rajasthan PSC spread across the units of Mechanics of Tillage & Traction (Soil Dynamics). Difficulty: 24 easy, 5 medium, 0 hard.
| Longitudinal and lateral stability | 4 | |
| Traction theory: slip, rolling resistance and net traction | 3 | |
| Wheel and track mechanics | 3 | |
| Cone index and cone penetrometer | 3 | |
| Prediction of draft | 2 | |
| Tractive efficiency | 2 | |
| Weight transfer | 2 | |
| Determination of the centre of gravity | 2 | |
| Tractor chassis mechanics | 2 | |
| Soil compaction by vehicles | 2 | |
| Traction in wetland soils | 2 | |
| Dynamic properties and strength of soil | 1 | |
| Soil-tool mechanics | 1 |
Choose an answer, then open the working. Each explanation says why the right answer is right and why the others are not.
In a disc harrow, why are the front gangs set at opposite angles?
B. So that their side forces largely cancel
Each angled gang produces a side force; opposing gangs balance them so the harrow runs straight. Vertical load is still needed for penetration, and draft cannot be zero.
A tractor covers a marked distance in 17 drive-wheel revolutions without load and in 20 revolutions when pulling a plough. What is the slip?
D. 15.0 %
s = 1 − N0/N1 = 1 − 17/20 = 15.0 %. Using (N1 − N0)/N0 = 17.6 % is the common wrong basis: slip is referred to the loaded revolutions (theoretical travel). 85.0 % is N0/N1 itself; 8.1 % divides the difference by the sum of the revolutions.
An engine delivers 40 kW; transmission efficiency is 0.90 and tractive efficiency 0.70. What drawbar power is available?
C. 25.2 kW
Drawbar = 40 × 0.9 × 0.7 = 25.2 kW. Ignoring the transmission gives 28.0 kW; dividing gives more than engine power, which is impossible. Dividing gives 63.5 kW; 36.0 kW ignores the tractive efficiency.
A level tractor weighs 32 kN in total and its front axle reads 9.6 kN on a platform scale. The wheelbase is 2.4 m. How far ahead of the rear axle is the CG?
A. 0.72 m
Moments about the rear axle: Wf·L = W·x → x = 9.6 × 2.4/32 = 0.72 m. Using the rear reading gives the distance from the front axle, 1.68 m. 0.30 m forgets to multiply by L; 1.03 m divides by the rear reading (22.4 kN) instead of the total.
A tractor with a track width of 1.5 m weighs 28 kN. The right-side wheels carry 14.7 kN. How far is the CG from the left wheel line?
C. 0.787 m
Moments about the left wheel line: W_right × t = W × y → y = 14.7 × 1.5/28 = 0.787 m, slightly right of centre (0.037 m). Using the left reading gives the distance from the right wheel line. 0.713 m uses the left reading; 0.750 m assumes the CG is central; 0.394 m uses half the track.
Of several passes of the same wheel in one track, which usually causes the largest increase in bulk density?
B. The first pass
Most compaction occurs on the first pass; later passes add less each time but push compaction deeper. This is why confining traffic to fewer tracks helps.
Why are cage wheels used on power tillers in puddled rice fields?
A. They sink through soft mud to the firmer layer, grip it with lugs and do not clog with mud
Cage wheels are open, lugged steel wheels; they reach the hardpan and engage it while shedding mud. Floats, not cage wheels, carry weight on the surface.
The coefficient of rolling resistance of a towed wheel is
D. rolling resistance divided by wheel load
RR/W is a dimensionless coefficient; it is small on firm roads and several times larger on soft or tilled soil.
Which change improves the lateral stability of a tractor working across slopes?
A. Setting the rear wheels to a wider track
Lateral stability depends on half track over CG height. A wider track increases the base; raising loads or removing low ballast raises the CG.
Ten here, 29 in the app. The Laisha app has every practice question we have written to Rajasthan PSC in this subject, marked as you go, with timed papers, a jump-to-unanswered list and a certificate when you pass at 70 per cent.
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