What type of brake is specifically used to measure brake horsepower?

To measure brake horsepower, the correct type of brake utilized is the friction brake. This is because friction brakes operate by converting the kinetic energy of a rotating shaft into thermal energy through friction. When used in a dynamometer setup, they allow for precise calculations of the power being translated into work.

In dynamometers, friction brakes can be measured by the amount of load they can apply against the rotation of the engine or device being tested, making it possible to derive the brake horsepower by assessing the rotational speed and the applied load. This configuration provides an effective means of determining the engine's performance under specific operating conditions.

Other brake types, such as drum brakes, disc brakes, and hydraulic brakes, primarily focus on stopping or slowing down a vehicle rather than measuring power output in a testing environment, which does not serve the same purpose in assessing brake horsepower.