Question

Given below are two statements, one is labelled as Assertion A and the other is labelled as Reason R
Assertion A: Operating with restrained links rather than free links provides greater tractive ability
Reason R: Operating with restrained links increases the vertical load on the tractor rear wheels.
In light of the above statements, choose the correct answer from the options given below

• A. Both A and R are true and R is the correct explanation of A
• B. Both A and R are true but R is NOT the correct explanation of A
• C. A is true but R is false
• D. A is false but R is true

Hint:

To maximize tractor traction, engineers utilize dynamic weight transfer.
By restraining the hitch links, the implement's resistance is redirected to push down on the rear wheels, converting draft resistance into productive traction.

Answer 1

The Correct Option is A

Step 1: Understanding the Concept:
Tractor tractive ability depends on the friction between the drive tires and the soil.
The maximum draft or pulling force a tractor can develop is directly proportional to the normal force acting on its drive wheels.
Key Formula or Approach:
The maximum tractive force (\(F\)) of a wheel is governed by: \[ F = \mu \cdot W_r \] where:
- \(\mu\) is the coefficient of traction.
- \(W_r\) is the dynamic vertical load acting on the drive (rear) wheels.

Step 2: Detailed Explanation:
Let us analyze Assertion A:
The three-point hitch of a tractor can be operated with either free links or restrained (rigid) links.
Operating with restrained links locks the relative vertical movement between the tractor and the implement.
This mechanical coupling allows forces to be transferred directly between the two systems.
Under load, this increases the tractor's overall draft capacity and tractive ability.
Thus, Assertion A is true.
Let us analyze Reason R:
When the hitch links are restrained, the draft (horizontal pull) of the implement creates a rotational moment about the rear axle.
This moment transfers weight from the front wheels of the tractor to the rear wheels.
Additionally, the vertical component of the implement's weight and soil downward force is transferred directly to the rear axle.
This dynamic weight transfer significantly increases the vertical load on the rear drive wheels.
Thus, Reason R is true.
Since the increase in vertical load on the rear wheels (R) directly increases traction (A), the reason is the correct explanation of the assertion.

Step 3: Final Answer:
Both Assertion A and Reason R are true, and Reason R is the correct explanation of Assertion A.