Question

As part of an investigation, students are required to build a device that transforms thermal energy to potential energy with an energy efficiency no less than 80%. One group of students builds a remote-controlled car that is able to push a ball along the path of a maze. Tests show that for each 5.0 J of work input, the work output is about 3.8 J. Which statement correctly describes whether the car meets the device requirements?

A. No. Even though it does transform thermal energy to potential energy, it does not meet the efficiency requirement.

B. Yes. It meets the efficiency requirement, and it transforms thermal energy to potential energy.

C. No. It does not meet the efficiency requirement, and it does not transform thermal energy to potential energy.

D. No. Even though it does meet the efficiency requirement, it does not transform thermal energy to potential energy.

Answer 1

The remote-controlled car does not meet the efficiency requirement because it has an efficiency of 76%, which is less than the required 80%. Thus, the correct answer is A: No, the car does not meet the efficiency requirement, even though it may transform thermal energy to potential energy.

Step-by-step explanation:

The question at hand involves determining whether the students' remote-controlled car, which pushes a ball along the path of a maze, meets the requirement of transforming thermal energy into potential energy with an efficiency of no less than 80%. When assessing the car's performance, we find that for every 5.0 J of work input, the work output is about 3.8 J. To calculate the efficiency of the car, we divide the work output by the work input and multiply by 100 to get a percentage:

Efficiency = (Work Output / Work Input) × 100 = (3.8 J / 5.0 J) × 100 = 76%

Since the calculated efficiency of 76% is less than the required 80%, the answer to the student's question is:

A. No. Even though it does transform thermal energy to potential energy, it does not meet the efficiency requirement.

Furthermore, the transformation of thermal energy into potential energy is questionable here, as the car seems to utilize electrical energy to perform work. To comply with the efficiency requirement of at least 80%, the efficiency of the energy transformation must be increased.