【通用版】2018高考物理一轮复习 第5章 机械能及其守恒定律 第4节 功能关系 能量守恒定律教师用书.doc

1、 1 4 1 1 (1) (2) 2 (1) (2) (3) (4) 2 1 2 3 (1)E E E E 1 (1) (2) (3) (4) (5) (6) 2 ( ) 2 A B C D A A 3 A B F A B B F W1 Q1 B F W2 Q2 ( ) 92492233 A. W1 gL A B A C g (1) A C (2) (3) . 92492235 (1)A f 2 mgcos A C 2mgLsin 1 2 mv 2 0 1 2 mv 2 mgL fL v v 2 0 gL. (2) A C f x 0 1 2 3mv 2 x v 2 0 2g L 2 . (3

2、) C Ep mgx 2mgxsin fx Ep fx 3mv 2 0 4 3mgL 4 . (1) v 2 0 gL (2) v 2 0 2g L 2(3) 3mv 2 0 4 3mgL 4 2 7 3 10 m/s Ek Ep h g 10 m/s 2 ( ) A 0.2 kg B ( ) 0.20 N C 20 13m D 2 m 0.5 J D Ep mgh m 0.1 kg A E E fh E E E f 0.25 N B H mgH 1 2 mv 2 fH mgH 1 2 mv 2 1 2 mv 2 0 H 20 9m C h 2 m fh mgh Ek2 1 2 mv 2 0

3、Ek2 2.5 J Ep2 mgh 2 J 0.5 J D 1. (1) (2) 2 W Ff l Q Ff l 8 v0 2 m/s m 10 kg ( ) 1.9 s h 1.5 m g 10 m/s 2 5-4-8 (1) (2) (1)1.9 s vm 2 t h sin vm 6 1.9m/sv0 1.9 s (2) (3) (1) x h sin 3 m v0 x1 v t1 v0 2 t1 x x1 v0(t t1) t1 0.8 s x1 0.8 m a v0 t1 2.5 m/s 2 cos mgsin ma 3 2 . (2) t1 x v0t1 1.6 m t1 x x

4、x1 0.8 m 9 t1 Q cos x 60 J Ek 1 2 mv 2 0 20 J Ep mgh 150 J W Q Ek Ep 230 J. (1) 3 2(2)230 J 1 1 m v ( ) 92492236 A 1 2 mv 2B mv 2C 1 2 mv 2D D A 1 2 mv 2 B W mv 2 C D 2 2 ( ) v 2 m/s 10 m 1 kg A 1.2 s B 0.5 g 10 m/s 2 0.6 0.8. A B ( ) 92492237 A 2 J B 11.2 J C 4.8 J D 12.8 J BC mg(sin cos ) ma1 v a1t1 x1 1 2 a1t 2 1 a1 10 m/s 2 t1 0.2 s x1 0.2 m mg(sin cos ) ma2 v v a2t2 x2 vt2 1 2 a2t 2 2 t1 t2 1.2 s a2 2 m/s 2 v 4 m/s x2 3 m B Ek 1 2 mv 2 8 J A Wf 1cos 2cos 11.2 J 11.2 J B Q (vt1 x1 x2 vt2)cos 4.8 J C W 1cos 2cos 6.4 J D 1 2 3 Q Ff l l l