Final answer:
The stopping distance of a truck at a given velocity depends on a combination of reaction distance and braking distance, which requires knowledge of multiple factors such as initial velocity, reaction time, and deceleration rate. Without more information, it is not possible to validate the statement about the truck's stopping distance being 138 ft at 40 mph.
Step-by-step explanation:
The question involves understanding the stopping distance of a truck when it is traveling at a given velocity and the factors that affect it. The total stopping distance includes the distance the truck travels before the driver reacts and applies the brakes, also known as the reaction distance, and the distance it takes for the truck to come to a stop after the brakes are applied, known as the braking distance.
To calculate the total stopping distance, we need to know the initial velocity, the driver's reaction time, the deceleration rate due to braking, and other factors such as road conditions. For example, if a truck is traveling at a constant velocity of 10 m/s (approximately 22 mph) and the driver has a reaction time of 0.5 seconds, the reaction distance can be calculated by multiplying velocity by reaction time. Then, to find the braking distance, the deceleration rate is used in kinematic equations.
If the given stopping distance is 138 ft for an initial velocity of 40 mph, we can't validate the statement as true or false without additional information such as the truck's deceleration rate and the driver's reaction time. Therefore, without further information on road conditions, the weight of the truck, and other variables, it is not possible to confirm the truth of the statement.