Question

Kinetic and internal energy Mech 17 III. Application to Friction A. A block is initially moving on a level table. Later, it is observed that the block has slowed down due to friction. Time f Block slows down while moving on a level table In answering the following questions, consider the system consisting of only the block. 1. Complete the energy bar diagram at right. Explain your Block reasoning, including any assumptions you are making Did the block gain internal energy as a result of this process? If so, what type of internal energy do you think increased (e.g., chemical, thermal)? 2. Three students discuss their energy bar diagrams for this process. Student 1: "Since the energy is constant, the loss in kinetic energy of the block should equal the gain in internal thermal energy "That's only if the system is closed. We don't know that it is closed.: "Yes we do. We know the system is closed because only the block heats up. Student 2: Student 3: not the table. Friction only causes the moving object to get hotter. Do you agree with student 3's response to student 2? Explain. 3. Does the motion or state of the environment change? Explain. Do you still agree with your energy bar diagram above? If not, resolve any inconsistencies. 4.

Answer 1

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