Which of the following statements regarding the forces acting on a tillage tool are CORRECT?
Options:
(A) Draft is the horizontal component of the total soil reaction acting parallel to the direction of travel
(B) Side draft occurs when the line of pull does not coincide with the center of resistance in the horizontal plane
(C) Vertical force is always directed downwards irrespective of soil type and tool shape
(D) Specific draft is expressed as draft per unit tilled cross-sectional area
Answer Key:
A, B, D
Step-by-Step Solution & Explanation
- Option A is correct: Draft is defined as the horizontal component parallel to motion.
- Option B is correct: An eccentricity between line of pull and center of resistance creates a couple, resulting in side draft.
- Option C is incorrect: Vertical force can be upward or downward depending on the lift angle, suction, soil resistance, and dullness of the blade.
- Option D is correct: Specific draft is draft divided by cross-sectional area of the furrow slice ($N/cm^2$ or $kN/m^2$).