Consider a 2WD agricultural tractor pulling a horizontal drawbar load on level ground. Which of the following statements is/are CORRECT?
Options:
(A) The dynamic normal load on the rear axle increases as the drawbar pull increases
(B) The dynamic normal load on the front axle decreases with increasing drawbar pull
(C) Dynamic weight transfer is given by $\Delta W = \frac{P \cdot h_d}{x_w}$, where $h_d$ is drawbar hitch height and $x_w$ is wheelbase
(D) The tractor will overturn backward when the dynamic load on the rear axle becomes zero
Answer Key:
A, B, C
Step-by-Step Solution & Explanation
Tractor Mechanics Principles (Liljedahl et al.):
- **A is TRUE**: Rear load increases with drawbar pull due to weight transfer.
- **B is TRUE**: Front load decreases proportionally.
- **C is TRUE**: Dynamic weight transfer is $\Delta W = \frac{P h_d}{x_w}$.
- **D is FALSE**: Overturning (rearing) occurs when **front** axle reaction becomes zero ($R_f \le 0$), not rear.
Correct options: **A, B, C**.