GATE 2026 AG – Question 53
A tractor boom sprayer has 12 flat-fan nozzles of angle 110°. Adjacent footprints must overlap by 30% of a single footprint. Boom height is .60 m, theoretical speed 8 km/h, wheel slip 8%,and field efficiency 75%. Ignore other losses. Find time to spray 25 ha, in minutes, rounded to the nearest integer.
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Correct answer: 170 to 190
Explanation
One footprint has width $w=2h\tan(110^\circ/2)=1.2\tan55^\circ=1.71378$ m. Nozzle spacing is $s=.70w=1.19964$ m. With the standard repeated-pass working width $W=12s=14.3957$ m, actual travel speed is $8(1-.08)=7.36$ km/h. Effective capacity is $Wv\eta_f/10\approx7.9464$ ha/h. Thus time $=25(60)/7.9464\approx188.77$ minutes, rounded **189 minutes**. Counting the two exposed end half-patterns as full field coverage gives a different edge convention;the repeated-pass width avoids double-counting overlap.