Answer :
Final answer:
The normal air brake pressure for the rear/front of a 5-ton vehicle is 80 psi, thus the correct option is a.
Explanation:
The air brake system of a vehicle is an essential safety feature that helps in slowing down or stopping the vehicle. The air brakes work by using compressed air to create pressure and activate the brakes. The air brake pressure is measured in psi (pounds per square inch). In the given options, the correct answer is option A, with 80 psi for the rear and 100 psi for the front.
In order to understand why 80 psi is the correct answer, we need to know the working of the air brake system and how the pressure affects it. The air brake system has two main components - the air compressor and the air brake chambers. The air compressor is responsible for compressing air and sending it to the air brake chambers. The air brake chambers have a piston that expands when the air pressure is applied, causing the brakes to engage.
Now, in a 5-ton vehicle, the weight distribution is not equal on all axles. The front axle carries more weight than the rear axle. This means that the brakes on the front axle need to be stronger to slow down or stop the vehicle effectively. Hence, the front brake chambers need to have a higher air pressure than the rear brake chambers. This is why option A is the correct answer.
To further understand this, let's do a simple calculation. Let's assume the total weight of the vehicle to be 10,000 lbs, with 60% of the weight on the front axle and 40% on the rear axle. This means that the front axle carries 6,000 lbs, and the rear axle carries 4,000 lbs. Now, the air brake pressure needed for each axle can be calculated by dividing the weight on the axle by the total weight of the vehicle and then multiplying it by the total air brake pressure. For the front axle, it would be (6,000/10,000) x 100 psi, which equals 60 psi. For the rear axle, it would be (4,000/10,000) x 100 psi, which equals 40 psi. Therefore, the total air brake pressure for the front axle would be 60 psi + 20 psi (extra pressure for safety) = 80 psi, and for the rear axle, it would be 40 psi + 20 psi = 60 psi.
In conclusion, the normal air brake pressure for the rear/front of a 5-ton vehicle is 80 psi for the front and 60 psi for the rear. This ensures that the front brakes are stronger and can effectively slow down or stop the vehicle, while the rear brakes provide support and stability. It is important to maintain the correct air brake pressure to ensure the safe operation of the vehicle, thus the correct option is a.
