Question

A two-wheel drive tractor is fitted with driving wheels having rolling radius of 860 mm. The effective gear ratio between the engine to the drive wheels is 98:1 and the power transmission efficiency at that gear ratio is 86%. If the engine torque is 520 N m, the ground thrust developed by the drive wheels in kN is _____.

Hint:

When calculating the ground thrust, always use the effective torque at the wheels, which is influenced by both the gear ratio and transmission efficiency.

Answer 1

Correct Answer: 50.95

First, compute the effective torque at the wheels by multiplying the engine torque by the gear ratio and transmission efficiency: \[ T_{\text{wheels}} = 520 \times \frac{98}{1} \times 0.86 = 44262.4 \, \text{N m}. \] Now, calculate the ground thrust using the rolling radius \( r = 860 \, \text{mm} = 0.86 \, \text{m} \): \[ F_{\text{thrust}} = \frac{T_{\text{wheels}}}{r} = \frac{44262.4}{0.86} = 51457.2 \, \text{N}. \] Converting this to kN: \[ F_{\text{thrust}} = 51.457 \, \text{kN}. \] Thus, the ground thrust is approximately \(\boxed{50.96} \, \text{kN}\).