Final answer:
To test spring brakes automatically, drive at 50 mph and record the time or distance to stop, replicating a scenario where regular brakes fail. Figures illustrate brake mechanisms using Pascal's principle and tests ensure safety and efficiency under stress.
Step-by-step explanation:
To test that the spring brakes come on automatically in a vehicle, you can perform a controlled experiment that measures their effectiveness when the regular braking system fails. This is consistent with the principles of conditioning the brakes in case of an emergency. The process involves driving the vehicle at a specific speed and then applying the brakes until the vehicle comes to a complete stop. Two metrics can be recorded during this test: the time it takes for the vehicle to stop, and the distance it travels before coming to a complete halt.
For example, you could drive the car at exactly 50 mph, and then apply the brakes until it stops. You would record the time it takes for the car to stop as a measure of the brake's responsiveness. Alternatively, you could record the distance the car travels from the point the brakes are applied to where it comes to a stop, which would give you an indication of the efficiency of the brake system.
In the context of hydraulic brakes that use Pascal's principle, as seen in Figures 11.12, 11.17, and 14.18, the driver applies a force to the brake pedal. This force is amplified by a lever and the hydraulic system resulting in equal pressure transmitted to the wheel cylinders, which engages the braking system. With the assumption of identical slave or wheel cylinders, equal force output F2 is generated at each wheel to ensure balanced braking.
When testing the braking system in an airplane, as noted in the 'Construct Your Own Problem' section, it involves bringing the airplane to takeoff speed and then stopping it using the brakes only. This scenario would require calculations of the temperature increase in the brakes, which are indicative of the efficiency and safety of the brake system in withstanding high temperatures without causing a fire.