Which of these statements is true about large trucks?
They take longer to stop than passenger vehicles.
They all have air brakes that allow them to stop quickly.
They are more maneuverable than passenger vehicles.
The Correct Answer and Explanation is :
The correct answer is: They take longer to stop than passenger vehicles.
Explanation:
Large trucks, such as those used for freight transport, typically take longer to stop compared to passenger vehicles. This is due to several factors related to the weight, braking systems, and physics involved in stopping such large vehicles.
- Weight: Large trucks weigh much more than passenger vehicles, often several times heavier. The greater the mass of a vehicle, the more force is needed to bring it to a stop. This is based on Newton’s Second Law of Motion, which states that the acceleration (or deceleration, in this case) of an object is inversely proportional to its mass when the same amount of force is applied. Hence, the heavier the vehicle, the longer it takes to stop.
- Braking System: While many large trucks use air brakes, which are effective and reliable, they are not inherently quicker than the hydraulic braking systems typically found in passenger vehicles. Air brakes work by using compressed air to apply pressure to the brake system, and they tend to take longer to engage and fully apply compared to the more immediate response of hydraulic systems.
- Stopping Distance: The stopping distance of a large truck is significantly longer because of the vehicle’s size, weight, and the time it takes for air brakes to fully engage. On average, a large truck requires about 300-400 feet to come to a complete stop when traveling at 65 mph, whereas a passenger vehicle might need around 160-180 feet under the same conditions.
Why the other statements are false:
- “They all have air brakes that allow them to stop quickly”: While many large trucks use air brakes, these are not designed to stop the vehicle more quickly. Air brakes are reliable but can have a slower response time than the braking systems in passenger vehicles.
- “They are more maneuverable than passenger vehicles”: Large trucks are far less maneuverable than passenger vehicles due to their size, longer turning radius, and the difficulty in handling, especially at low speeds or in tight spaces.