North East Independent School District Physics I Unit 2: Vectors Clarifying Statements May, 2009 The following TEKS apply to the Vectors unit: (3) Scientific processes. The student uses critical thinking and scientific problem solving to make informed decisions. The student is expected to: (B) express laws symbolically and employ mathematical procedures including vector addition and right-triangle geometry to solve physical problems This unit is the foundation for projectile motion; it is important that students have the opportunity to explore vectors graphically and algebraically. Adding vectors graphically should include either the “tail to tip” or the parallelogram method, where the magnitude of the vector is relative to its size and the arrow indicates the direction. Key terms in the conceptual development are vector, scalar, resultant vector, components, head wind, tail wind and cross wind. Note that both the regular and Pre-AP Physics I courses should have the same conceptual development. However, the level of problem solving should differ due to the nature of the associated math course requirement. Regular Physics I Problem Solving: Students in regular physics should be exposed to using x and y components to find the magnitude of resultant vectors using the Pythagorean theorem. They should also work problems where resolving vectors into x and y components is necessary using Pythagorean triples and special right triangles. Regular Physics I equations: Pythagorean triples: 3, 4, 5: 37, 53, 90 degrees respectively 5, 12, 13: 23, 67, 90 degrees respectively 8, 15, 17: 28, 62, 90 degrees respectively 7, 24, 25: 16, 74, 90 degrees respectively Generally: if m<n and both are positive integers. Special right triangles 45, 45, 90: 30, 60, 90: Clarifying statements are intended to deepen teachers’ understanding of science concepts and serve as a guide for instructional design. They are not intended to serve as student instructional materials. This publication is the property of North East Independent School District. Duplication in whole or in part, outside of NEISD, is prohibited without express written permission from NEISD.