review
review
Chapter 1: Introduction Measurement, Estimating Page1-16 了解
Chapter 1: Introduction, Measurement, Estimating Page1-16 了解
Chapter 2&3: Kinematics 2-1-2-7:一维运动,了解概念。(p16-34) 2-8: Use of calculus, Variable Acceleration 会用积分求速度和加速度。(p3435) 3-1,3-2,3-3,3-4and3-5(p44-51);7-2(p151 152);11-1(p275-277) Vectors:知道如何计算 3-6: Vector Kinematics (p52-53) 3-7&3-8 projectile motion:了解,(p54-p61)
Chapter 2&3: Kinematics 2-1—2-7 :一维运动,了解概念。(p16-34) 2-8: Use of Calculus, Variable Acceleration 会用积分求速度和加速度。 (p34-35) 3-1,3-2,3-3,3-4 and 3-5 (p44-51); 7-2 (p151- 152) ; 11-1 (p275-277) Vectors:知道如何计算。 3-6: Vector Kinematics (p52-53) 3-7 & 3-8 projectile Motion: 了解,(p54-p61)
3-9 Uniform Circular Motion. 5-4 Nonuniform Circular Motion Dynamics of Uniform Circular Motion p62-63; p119-120; p113-115 3-10 Relative velocity:不要求(p6467)
3-9 Uniform Circular Motion, 5-4 Nonuniform Circular Motion & Dynamics of Uniform Circular Motion p62-63; p119-120; p113-115 3-10 Relative Velocity: 不要求 (p64-67)
PositionⅤ ector(位矢) P(x,y,z, t) For a cartesian system: r=xi+vi+zk Motion function(运动方程) F=()==x(t)i+y(t)j+z(0)k
Position Vector(位矢) r xi yj zk = + + r r t x t i y t j z t k = ( ) = = ( ) + ( ) + ( ) For a Cartesian system: Motion Function ( 运动方程): P (x,y,z,t ) i k j x y z (t0 ) r(t) (t ) z x y
nstantaneous velocity(瞬时速度) △ △M>0△tat x()+y(1)j+z( =vr+yuj+v,k=v(t) Instantaneous Acceleration Aνdνddr)d a=lim △→0△ t dtdt dt)dt
Instantaneous velocity (瞬时速度) : x t i y t j z t k dt d dt dr t r v t ( ) ( ) ( ) lim 0 = + + = = → v i v j v k v(t) x y z = + + = InstantaneousAcceleration: 2 2 0 d d d d d d d d lim t r t r t t v t v a t = = = = →
In a natural coordinate(自然坐标系): a=a,t+ann vdS- Tangentia| acceleration(切向加速度) 反映速度大小变化的快慢 - Radia| acceleration(法向加速度) R 反映速度方向的变化
In a natural coordinate (自然坐标系): 反映速度大小变化的快慢 --Tangential acceleration(切向加速度) --Radial acceleration(法向加速度) a = at τ ˆ + an n ˆ 2 2 dt d s dt dv at = = R v an 2 = 反映速度方向的变化
Circular Motion 1. Uniform Circular Motion(p62): 2. Nonuniform Circular Motion(p119): ∴a=W.n+ dv where at ora=ld|=√a4+ 2 P=arctan(a,/an)
Circular Motion 1. Uniform Circular Motion (p62): 2. Nonuniform Circular Motion (p119): a = an n + at where dt dv at = r v an 2 = or 2 2 a = a = at + an arctan( / ) = at an
运动学的两类问题: 1.第一类问题 已知运动学方程,求b,a 2.第二类问题 已知加速度和初始条件,求U,F
1. 第一类问题 a 已知运动学方程,求 v , 2. 第二类问题 已知加速度和初始条件,求 , r v 运动学的两类问题:
1.第一类问题已知运动学方程,求U,a 例已知一质点运动方程=2ti+(2-t2) 求(1)t=1s到t=2s质点的位移(2)t=2s时υ,a (3)轨迹方程 解(1)由运动方程得=2+j2=4i-2了 AF=一F=(4-2)+(-2-1)=21-3 dr d (2)b 21-21j dt 当t=2s时U2=2-4 (3)x=2ty=2-t2轨迹方程为y=2-x2/4
1. 第一类问题 a 已知运动学方程,求 v , (1) t =1s 到 t =2s 质点的位移 (3) 轨迹方程 (2) t =2s 时 a , v r i j 1 = 2 + r i j 2 = 4 − 2 r r r i j i j = 2 − 1 = (4 − 2) + (−2 −1) = 2 −3 已知一质点运动方程 r t i t j 2 (2 ) 2 = + − 求 例 解 (1) 由运动方程得 i t j t r 2 2 d d v = = − i j 2 4 v2 = − (2) 当 t =2s 时 a j 2 = −2 j t t r a 2 d d d d 2 2 = = = − v 2 x = 2t y = 2 − t 2 / 4 2 (3) 轨迹方程为 y = − x