解:x=41-2B (1)△x=x-0=41-23=4×2-2×23=-8m △x-8 U=△t 2 =-4ms U=dx=4-6t2=4-6×22=-20m/s dt (2)△x=x3-x2 =(4×3-2×3)-(4×1-2×13) 44m △x-44 U=△t=3-1 =-22m/s 结束目录x 0 解： x = 4t - 2t 3 （1）Δ =x 4t - 2t 3 = = 4×2 2×23 = 8 m t v = Δx Δ s = 8 2 = 4m 6 2 t v = dx = d 4 t 22 =4 6× = 20 m s = 4×3 2×33 4×1 2×13 ( ) ( ) = 44 m Δx = x3 （2） x2 t v = Δx Δ = s 44 3 = 22 m 1 结束 目录