The maximum power that can be extracted by a find turbine from an air stream is approximately P? =? ? ?u?3 where ?d is the blade diameter, ?u is the wind speed, and the constant ?k = 0.5 W · s3/m5. (a) Explain the dependence of ?P on ?d and on ?u by considering a cylinder of air that passes over the turbine blades in time ?t (Fig.). This cylinder has diameter ?d?, length L = ?u?t, and density ?. (b) The Mod-5B wind turbine at Kahaku on the Hawaiian island of Oahu has a blade diameter of 97 m (slightly longer than a football field) and sits atop a 58-m tower. It can produce 3.2 MW of electric power. Assuming 25% efficiency, what wind speed is required to produce this amount of power? Give your answer in m/s and in km/h. (c) Commercial wind turbines are commonly located in or downwind of mountain passes. Why? Figure:
The Psychology of Problem Solving Problem Solving Active efforts to achieve a goal Types of problems: ● Structure problems Find relationships ● Arrangement problems Arrange to satisfy a goal ● Transformation problem Carry out a sequence of transformation What screws us up 1. Irrelevant Information 2. Function fixedness 3. Mental set 4. Unnecessary constraints Approaches to Problem Solving 1. Trial & error Repeat until success 2. Heuristics Using experience to learn a. “Rule of thumb” 3. Forming subgroups Breaking problems down into many smaller parts 4. Working backward Solving problems starting from the end 5. Search for analogies Search for solutions that had worked before 6. Change the representation Risky Decision Making Factors: ● Objective value The value is within itself ● Subjective utility A decision based on the individual’s cost and benefit. ● Subjective probabilities An individual’s judgment on whether an outcome is going to occur. Common Probability Bloopers Availability bias How quickly it comes to mind Representativeness bias A tendency that seems more typical, it is more probable Ignoring base rates Make a judgment on the outcome without considering prior knowledge of the probability The conjunction fallacy More probability for one group, then one group + another group The gambler’s fallacy Increase chance if the result happen before hand Ignoring sample size Choose the smaller sample size that fits the condition The Psychology of Language Acquisition 3 Criteria of Language 1. Symbolic 2. Structured 3. Infinitely generative Structure of Language Phonemes Very small unit of sound Morphemes Very small unit of meaning Syntax Use a series of words to create a sentence The vocabulary spurt: 18 months Example Sentence: The boys cried Word: 3 Morphemes: 5 (The / boy/s / cri/ed) Phonemes: 9 (Th/e / b/oi/z / k/r/i/d) Language Acquisition Babbling Make phonemes (Make different sounds) Holophrases Able to communicate with one word that will act as a sentence Telegraphic speech Make a sentence out of two words. (noun and verb) Whole sentence Make sentences grammatically correct Metalinguistic awareness Realization of language having more than one meaning. Theories of Language Acquisition Behaviorist ● Skinner ● Imitation, reinforcement Nativists ● Chomsky ● Innate Language Acquisition Device ● Original sentence ● Overregularization Language Shapes Thought Linguistic Relativity refer to more words you know, the more complex it can be. Basically add adjectives before a noun. Framing Study of how choice affect the person Semantic slanting label use to bring emotion or numb emotion Language Comprehension Words recognition Recognize written and spoken words correctly and virtually. Advantage of nonverbals more information and understanding (body language) Extraneous Noise Noise that don’t do anything to what you are saying; “um”, “you know” Animals Thinking Classical conditioning Operant conditioning Observational learning Rudimentary counting being able to “count” the more “favored” portion for them. Limited insight Be able to use the supply of what’s around to achieve a goal. Exhibit Language Communicate Yes Language No The animal did not meet the criteria of language.