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GATE 2025 AG – Question 54

Farm Power · Tractors and Power Tillers · 2 marks · Numerical answer

An engine at 1200 rpm drives a rigid 1.2 m diameter wheel at 5 km/hour without slip or deformation. Gear reductions are 3:1 in the gearbox,4:1 in the differential and n:1 in the final drive. Find n, to two decimals.

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Correct answer: 4.20 to 4.70

Explanation

Forward speed is $5000/60=83.3333$ m/min. Wheel speed is $N_w=v/(\pi D)=83.3333/(\pi1.2)=22.10485$ rpm. Overall reduction is $1200/N_w=54.28672$,which equals $3(4)n$. Thus $n=54.28672/12=\mathbf{4.52}$. All ratios here represent speed reductions.

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