Subtopic: Thermodynamic principles of I.C. engines
Question Statement:
A rear-wheel drive tractor has a wheelbase of $2.1\text{ m}$. The static weight on the front axle is $8.0\text{ kN}$ and on the rear axle is $14.0\text{ kN}$. A horizontal drawbar pull of $7.0\text{ kN}$ is applied at a hitch height of $0.45\text{ m}$ above the ground. Calculate the dynamic weight on the rear axle in $\text{kN}$ (round off to 2 decimal places).
Answer Key:
15.5
Step-by-Step Solution & Explanation
Weight transfer from front to rear axle due to drawbar pull $P$ at hitch height $h_d$ on wheelbase $L$:
$\Delta W = \frac{P \times h_d}{L} = \frac{7.0\text{ kN} \times 0.45\text{ m}}{2.1\text{ m}} = \frac{3.15}{2.1} = 1.50\text{ kN}$
Dynamic weight on rear axle:
$R_{dr} = R_{sr} + \Delta W = 14.0 + 1.50 = 15.50\text{ kN}$
Acceptable range: $15.3 - 15.7\text{ kN}$.