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部分区期末练习高三物理答案 第 1 页(共 3 页)
天津市部分区 2020~2021 学年度第一学期期末练习
高三物理参考答案
第Ⅰ卷共 8 题,每题 5 分,共 40 分。
1.D 2.C 3.B 4.C 5.B 6.BC 7.AD 8.BC
第Ⅱ卷共 4 题,共 60 分。
9.(12 分)
(1)①9.82(2 分) ②铝棒上墨线 A 点的速度不为零(2 分)
(2)①A1:R1(各 2 分)
②0.83(0.80~0.87 范围内都给分);1.42(1.40~1.44 范围内都给分)(各 2 分)
10.(14 分)解:
(1)设地球的质量和半径分别为 M0 和 R0,火星的质量和半径分别为 M 和 R,由于忽略
星球的自转,对质量为 m 的物体,由万有引力定律得
地球上
0
02
0
M m
G mg
R
·························································· ········(2 分)
火星上 2
Mm
G mg
R
···································································(2 分)
代入数据解得
24m / sg ·······························································(2 分)
(2)对小球受力分析,由已知条件可知 37
在竖直方向上,由平衡条件得
cos mgF ············································································(2 分)
代入数据解得 5NF ····································································(2分)
(3)对小球在水平方向上,由牛顿第二定律得
2π
2s n in
4
i s
T
F m L θ ··············(2 分)
代入数据解得
π2 5
5
T s ·······················································(2 分)
部分区期末练习高三物理答案 第 2 页(共 3 页)
11.(16 分)解:
(1)由图像可知 0 6m / sv ,
2
1 2m / sa ··········································(2 分)
在沿杆方向上,对小球由牛顿第二定律得
1sin cos( ) ( )F mg F mg ma ··········································(2 分)
代入数据解得 40NF ·······························································(2 分)
(2)2s 末小球速度 1 0 1 10m / sv v a t ·········································· ··(1 分)
0—2s 小球的位移大小 11
2
0
1
2
x v t a t ············································(1 分)
代入数据解得 1 16mx ····································································(2 分)
2s 后,对小球由牛顿第二定律得
2sin cosmg mg ma ···························································(2 分)
代入数据解得
2
2 10m / sa ····························································(1 分)
2s 后沿倾斜细杆向上运动的位移大小
2
1
2
22
5m
v
x
a
····························(1 分)
小球向上运动到最高点距出发点的距离为 1 2x x x ·································(1 分)
代入数据解得 21mx ··································