Key word particle frame of reference position displacement average(instantaneous) velocity average ( instantaneous )acceleration speed free fall acceleration due to gravity projectile trajectory derivative normal component 个公的 tangential component
particle frame of reference position displacement average (/instantaneous) velocity average (/instantaneous ) acceleration speed free fall acceleration due to gravity projectile trajectory derivative normal component tangential component Key word:
1. Basic Concepts 1.1 Ideal model Particle: It is the body that has only the mass, but not its shape and size a pingpong the earth Which one is a particle? Ideal Models: Simple pendulum, rigid body, point charge, harmonical oscillator
1.1 Ideal Model ◼ Particle: It is the body that has only the mass, but not its shape and size. Which one is a particle? a pingpong the earth Ideal Models: Simple pendulum, rigid body, point charge, harmonical oscillator… 1. Basic Concepts
1.2 Frame of reference and coordinate axis Frame of Reference: relative, usually refer to earth X Moon Earth Venus Sun Mars
1.2 Frame of Reference and Coordinate Axis ◼ Frame of Reference: relative, usually refer to earth o x
The Coordinate System: math conception attached to the real-word bodies Q Path Cartesian natural Other coordinates: polar, spherical, cylindrical elliptical
◼ The Coordinate System: math conception attached to the real-word bodies Cartesian natural Other coordinates: polar, spherical, cylindrical, elliptical…
1.3 Scalars and vectors Scalar: described by a single number with a unit, such as 1kg(mass), 105kg/m (density), 1A(electrical current Vector: has both magnitude and a direction such as E B/N Represe nt by: A: Unit vector A=/42=A1 B=A.C=-A
1.3 Scalars and Vectors ◼ Scalar: described by a single number with a unit, such as 1kg(mass), 103kg/m3 (density), 1A(electrical current). ◼ Vector: has both magnitude and a direction, such as r v a E , , , Represe nt by: A A A A ˆ AA ˆ = = M N A A ˆ B C A :Unit vector ˆ B A C A = , = −