Mechanics � The study of how matter and forces interact by alextt


									Aim  What is the difference between Speed and Velocity? I Kinematics - the description of motion without regard to the force that created the motion. (Mechanics – The study of how matter and forces interact.) A. Describing Linear Motion 1. Distance – The length of a path from one point to another. 2. Displacement – The length and direction of a straight-line path from one point to another. (can be positive or negative) Example. A student walks 3 meters south and 4 meters to the east. Determine the distance and displacement. 3. Scalar – Quantities (magnitude) that do not involve direction. a. examples; include time, distance 4. Vector – Include both a magnitude and direction. 5. Speed – the magnitude of the velocity without regard for direction a. speed (v bar) = distance / time 6. Velocity - A vector quantity that represents the rate at which an objects displacement changes 1. Velocity is a measure of displacement/time or v=d/t B. Practice Problems 1) A car travels 2.1 km south in 7.0 minutes. Find the velocity in m/s. Convert to si units (meters and seconds) Plug in and solve 5.0 m/s 2) A car travels 600. meters one way with a speed of 40 m/s and then travels 600 m/s in another way at 20 m/s. What is the car’s average speed? Average speed = total distance/time Total distance is easy 1200 meters To solve for time you must plug into v=d/t (Times come to 15 s and 30 s = 45s) 1200m/45s = 27 m/s 3) The average speed of a runner in a 400 meter race is 8.0 m/s. How long did it take the runner to complete the race? Plug in, cross-multiply and solve 50 seconds. 4) An object travels for 8.0 seconds with an average speed of 160 m/s. The distance traveled is? 1280 m 5) An object is displaced 12 meters to the right and then 16 meters upward. Find the displacement and the distance. Distance = 28 meters Displacement = 20 meters toward the NE at 53 using the cos 0 = 16/12 Give out regents questions for additional practice and Derek’s HW-3

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