Final answer:
The safe speed for going down a steep downgrade is determined by the steepness of the grade, the road conditions, and the total weight of the vehicle and cargo. Considering these factors together will help determine the most appropriate speed for safety.
Step-by-step explanation:
The question asks, which of the following determines the safe speed for going down a steep downgrade? The correct answer to this question is all of the above:
- The steepness of the grade
- The road conditions.
- The total weight of the vehicle and cargo
The steepness of the grade affects the vehicle's acceleration due to gravity, which impacts the speed at which the vehicle can safely travel. Road conditions can alter how much traction the vehicle's tires can maintain. The total weight of the vehicle and cargo influences the momentum of the vehicle and its stopping distance. Considering all these factors together is crucial for determining a safe speed when descending a steep grade.