Brake horsepower is measured at the engine's __________.

Brake horsepower is measured at the engine's flywheel. This is the point where the engine's output can be quantified in terms of the power produced. The flywheel is a crucial component since it serves to stabilize the rotational speed of the engine and store energy. By measuring the horsepower at the flywheel, one gets an accurate representation of the engine’s ability to perform work without the losses introduced by the drivetrain, transmission, or other accessories.

The measurement taken at this location allows for a more direct assessment of the engine's performance characteristics because the flywheel directly connects to the engine's output. It effectively reflects the engine's capability before the power is consumed by other systems.