Question

What is the speed required if a tractor engine has constant horsepower, to get high torque at the rear wheel?

• A. Very High
• B. High
• C. Low
• D. Constant

Hint:

To increase torque in a tractor with constant power, reduce the speed. Torque is inversely proportional to speed when power is constant.

Answer 1

The Correct Option is C

Step 1: Understanding the Torque-Speed Relationship
Torque (\( T \)) and power (\( P \)) in an engine are related by: \[ P = T \times \omega \] where: - \( P \) = Power (constant in this case) - \( T \) = Torque (Nm) - \( \omega \) = Angular speed (rad/s) Rearranging the equation: \[ T = \frac{P}{\omega} \]
Step 2: Effect of Lower Speed on Torque
Since power remains constant, reducing speed (\( \omega \)) will result in an increase in torque (\( T \)). This means: - At lower speed, torque is higher. - At higher speed, torque decreases.
Step 3: Eliminating Incorrect Options
- "Very High" and "High" speeds decrease torque, making these incorrect. - "Constant" is incorrect as torque varies with speed.
Step 4: Conclusion
For maximum torque at the rear wheels, the engine must run at a lower speed.