Question

technician a says that in a self-energizing brake, the rotation of the drum decreases the braking force of the lining against the drum. technician b says that the force of the brake drum is added to the force supplied by the wheel cylinder. who is correct?

Answer 1

Technician B is correct; in self-energizing brakes, the rotation of the drum adds to the braking force rather than decreasing it, leveraging the force supplied by the wheel cylinder.

Step-by-step explanation:

In a self-energizing brake, the rotation of the drum does not decrease the braking force; rather it can increase the force of the brake shoe on the drum. This means that Technician B is correct in stating that the force of the brake drum is added to the force supplied by the wheel cylinder. Hydraulic brakes, as mentioned in the reference figures, use Pascal's principle where pressure created in the master cylinder by the driver applying a force on the brake pedal is transmitted equally to the wheel cylinders. If we look at the example provided with the 100 N force being applied to the brake pedal resulting in a 500 N force exerted on the pedal cylinder, we can calculate the force on each wheel cylinder using Pascal's principle and the cross-sectional areas of the master and wheel cylinders. The increase in braking force from the rotation of the drum in self-energizing brakes makes the braking more effective while requiring less effort from the driver.