ES 105 Projectile and Rotational Motion 6 March 2007 I. Newton’s first law A. Object at rest , or in motion, stays in same state of motion unless acted upon by external force B. Examples 1. car and driver a. car stopped by wall—the external force b. driver not stopped by wall—no external force 2. vertical projectile a. loses speed at ~10m/s2 b. speed at minimum at top of projectile path II. Projectile examples A. Cannonball 1. without gravity 2. gravity is external force a. horizontal acceleration is zero—no change in speed b. vertical acceleration is ~10m/s2 B. airplane and package problem 1. 40 m/s forward velocity of plane and package 2. falls to directly below the plane C. cannonball shot at angle 1. path diagonal without gravity 2. path parabola with gravity D. Monkey and zookeeper animations 1. Without gravity—straight to him 2. With gravity—fast shot 3. With gravity—slower shot E. calculate how fast cannon ball is going in vertical and horizontal direction 1. horizontal speed constant 2. vertical speed varies with time 3. overall speed calculated with vectors of each, added together III. Projectile Range A. Steepness affects how long it is in the air 1. complementary angles have same range 2. greatest range at 45o angle B. vertical speed is zero at top of trajectory C. consider air resistance IV. Calculations of speed A. Baseball from 5 m platform 1. know height and distance of throw 2. know vertical d=(1/2)gt2, g, and d 3. find t to fall 4. divide horizontal distance by t B. Curvature of Earth= 5 m vertical for each 8000 m horizontal1. if you could throw 8000 m/s, ball would never reach the ground 2. same principle for orbiting objects V. Rotational speed A. Directly proportional to distance from center of rotation B. Cones roll in circles 1. smaller diameter goes slower, less distance in one rotation 2. greater diameter goes faster, further in one rotation 3. this is why train wheels are made like they are VI. Newton’s laws of motion A. First law B. Second law C. Third
View Full Document
Unlocking...