Question Bank • QB_FM_078 NAT • 2 Marks

Section 2: Farm Machinery

Farm Machinery

Subtopic: Functional requirements, principles of working, construction and operation of manual, animal, tractor and renewable energy operated equipment for tillage, sowing, planting, fertilizer application, inter-cultivation, spraying, mowing, chaff cutting, harvesting and threshing

Question Statement:

In a reciprocating mower, the stroke length of the knife is $76.2\text{ mm}$ and the crank operates at $900\text{ rpm}$. Calculate the average cutting velocity of the knife in $\text{m/s}$.

Answer Key:

2.286

Step-by-Step Solution & Explanation

In one revolution of the crank, the knife travels two stroke lengths (out and back): Distance travelled per revolution $= 2 \times S = 2 \times 0.0762 = 0.1524\text{ m}$. For a crank speed of $N = 900\text{ rpm}$ ($n = \frac{900}{60} = 15\text{ rev/s}$): $v_{\text{avg}} = 2 \times S \times \frac{N}{60} = 2 \times 0.0762 \times 15 = 2.286\text{ m/s}$
← Previous (QB_FM_108) Next (QB_FM_ADV_036) →

Practice In Authentic CBT Exam Interface

Test your skills under authentic timed conditions with live scoring and AIR percentile ranking.

Launch CBT Mock Test