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 horizontal 1 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 law
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