Question

On the average Semi-trailer truck, assuming an average load, can the engine overcome the brakes and continue spinning the wheels despite the operator applying the brakes fully?

This would be assuming the brakes are in good operating condition, and are not overheated or failing in some way.

Additionally, would this also be the case if the tractor unit had no trailer on it, and no weight? How about fully loaded?

Answer 1

Truck brakes used to control speed on a downhill run do work by converting gravitational potential energy into increased internal energy of the brake material.

The engine cannot overcome the brakes and continue spinning the wheels despite the operator applying the brakes fully on an average semi-trailer truck, assuming an average load and brakes in good operating condition.

Step-by-step explanation:

Truck brakes used to control speed on a downhill run do work by converting gravitational potential energy into increased internal energy of the brake material, preventing the energy from being converted into kinetic energy of the truck.

Truck brakes used to control speed on a downhill run do work by converting gravitational potential energy into increased internal energy of the brake material.

The engine cannot overcome the brakes and continue spinning the wheels despite the operator applying the brakes fully on an average semi-trailer truck, assuming an average load and brakes in good operating condition.

However, if the truck is fully loaded and the brakes are in good operating condition, the engine cannot overcome the brakes and continue spinning the wheels despite the operator applying the brakes fully.

This is because the mass of the truck is much larger compared to that of the brake material, and the temperature increase may occur too fast for sufficient heat transfer from the brakes to the environment.