2019浙教七年级下册科学第3章运动和力第1节机械运动知识点练习含含解析四十一

2021浙教版七年级下册科学[第3章运动和力第1节机械运动]知识点练习[含含解析]四十一2021浙教版七年级下册科学[第3章运动和力第1节机械运动]知识点练习[含含解析]四十一2021浙教版七年级下册科学[第3章运动和力第1节机械运动]知识点练习[含含解析]四十一最新教育资料优选优选2021-2021年浙教版初中七年级下册科学[第3章运动和力第1节机械运动]知识点练习[含答案解析]四十一第1题【单项选择题】“骑车的速度比步行的速度快〞，这句话表示( )A、骑车的人经过的行程比步行的人经过的行程长B、经过的行程相等时，骑车的人所用的时间比步行的人多C、在同样的时间内，骑车的人经过的行程比步行的人经过的行程长D、以上说法都不对【答案】：【解析】：第2题【单项选择题】人对着山崖喊话，经过2秒听到回声，喊话人到山崖的距离是( )A、680米B、340米C、170米D、17米【答案】：【解析】：1/12最新教育资料优选第3题【单项选择题】有一高度为H的田径运发动正在进行100米的竞赛，在终点处，有一站在跑道旁边的拍照记者用照相机给他拍摄冲线运动，拍照记者使用的照相机的光圈〔控制进光量的多少〕是16，快门〔曝光时间〕是有误秒，获取照片后测得照片中人的高度为h，胸前号码布上模糊局部的宽度是有误，由以上数据可以知道运发动的( )A、100米成绩B、冲线速度C、100米内的均匀速度D、人离照相机的距离【答案】：【解析】：第4题【填空题】某次跳伞时，一运发动重为600N，凑近地面时，可以为是竖直向下做匀速直线运动，当运发动离地面12m时速度为3m/s，那么运发动此后处落到地面所用的时间是______s，这12m内重力对运发动做的功是______J【答案】：【解析】：2/12最新教育资料优选第5题【填空题】小阳利用磁敏电阻为他的自行车设计了一个速度计，磁铁固定在自行车的辐条上，磁敏电阻固定在自行车的后车架上，安装表示图如图甲，工作电路如图乙，电源电压为6V恒定不变。当磁铁与磁敏电阻Rs靠得近来时阻值为200Ω，磁铁与磁敏电阻Rs离得最远时阻值为400Ω，凑近或远离时的实质电阻在这两者之间变化；当R0两头电压不低于4.5V时电子计数器就能有效计数，低于4.5V就不可以产生计数，车轮每转动一圈就计数一次。为保证电子计数器有效工作，电阻R0最小阻值______Ω。某次行驶中，小明发现5分钟恰巧圆满计数了300次，车轮的周长为3m，那么这段时间内自行车行驶的均匀速度为______km／h。【答案】：【解析】：第6题【填空题】2021年5月21日，我国成功发射了“嫦娥四号〞的中继卫星“鹊桥号〞，它将成为“嫦娥四号〞与地球间的“通讯桥梁〞“鹊桥号〞＂质量为448千克，发射后随火箭竖直升空1000米的过程中，“鹊桥号〞需战胜重力做功______焦。3/12最新教育资料优选假定地月间距离为3.8×10^5千米，电磁波速度为3×10^5千米/秒，在月球上发出的电磁波抵达地球需______秒。〔计算结果保留1位小数〕如图是月球反面照片，此中A处是______。【答案】：【解析】：第7题【填空题】有一句歌词：“月亮在白莲花般的云朵里穿行⋯〞这类描绘是以______为参照物的．A、云彩【答案】：【解析】：第8题【解答题】飞机的发动机是一种热机，经过航空煤油在气室中焚烧，从喷口向后高速喷出气体，使发动机获取向前的推力，高空中某飞机获取1.6×10^5N的水平推力，以600km/h的速度沿水平方向匀速航行1h，需要完全焚烧热值为4×10^7J/kg的航空煤油4000kg．求1h内：4/12最新教育资料优选<!--{cke_protected}{C}%3C!%2D%2D%5Bif%20gte%20mso%209%5D%3E%3Cxml%3E%0A%20%3Cw%3AWordDocument%3E%0A%20%20%3Cw%3AView%3ENormal%3C%2Fw%3AView%3E%0A%20%20%3Cw%3AZoom%3E0%3C%2Fw%3AZoom%3E%0A%20%20%3Cw%3APunctuationKerning%3E%3C%2Fw%3APunctuationKerning%3E%0A%20%20%3Cw%3ADrawingGridVerticalSpacing%3E7.8%20%E7%A3%85%3C%2Fw%3ADrawingGridVerticalSpacing%3E%0A%20%20%3Cw%3ADisplayHorizontalDrawingGridEvery%3E0%3C%2Fw%3ADisplayHorizontalDrawingGridEvery%3E%0A%20%20%3Cw%3ADisplayVerticalDrawingGridEvery%3E2%3C%2Fw%3ADisplayVerticalDrawingGridEvery%3E%0A%20%20%3Cw%3AValidateAgainstSchemas%3E%3C%2Fw%3AValidateAgainstSchemas%3E%0A%20%20%3Cw%3ASaveIfXMLInvalid%3Efalse%3C%2Fw%3ASaveIfXMLInvalid%3E%0A%20%20%3Cw%3AIgnoreMixedContent%3Efalse%3C%2Fw%3AIgnoreMixedContent%3E%0A%20%20%3Cw%3AAlwaysShowPlaceholderText%3Efalse%3C%2Fw%3AAlwaysShowPlaceholderText%3E%0A%20%20%3Cw%3ACompatibility%3E%0A%20%20%20%3Cw%3ASpaceForUL%3E%3C%2Fw%3ASpaceForUL%3E%0A%20%20%20%3Cw%3ABalanceSingleByteDoubleByteWidth%3E%3C%2Fw%3ABalanceSingleByteDoubleByteWidth%3E%0A%20%20%20%3Cw%3ADoNotLeaveBackslashAlone%3E%3C%2Fw%3ADoNotLeaveBackslashAlone%3E%0A%20%20%20%3Cw%3AULTrailSpace%3E%3C%2Fw%3AULTrailSpace%3E%0A%20%20%20%3Cw%3ADoNotExpandShiftReturn%3E%3C%2Fw%3ADoNotExpandShiftReturn%3E%0A%20%20%20%3Cw%3AAdjustLineHeightInTable%3E%3C%2Fw%3AAdjustLineHeightInTable%3E%0A%20%20%20%3Cw%3ABreakWrappedTables%3E%3C%2Fw%3ABreakWrappedTables%3E%0A%20%20%20%3Cw%3ASnapToGridInCell%3E%3C%2Fw%3ASnapToGridInCell%3E%0A%20%20%20%3Cw%3AWrapTextWithPunct%3E%3C%2Fw%3AWrapTextWithPunct%3E%0A%20%20%20%3Cw%3AUseAsianBreakRules%3E%3C%2Fw%3AUseAsianBreakRules%3E%0A%20%20%20%3Cw%3ADontGrowAutofit%3E%3C%2Fw%3ADontGrowAutofit%3E%0A%20%20%20%3Cw%3AUseFELayout%3E%3C%2Fw%3AUseFELayout%3E%0A%20%20%3C%2Fw%3ACompatibility%3E%0A%20%20%3Cw%3ADoNotOptimizeForBrowser%3E%3C%2Fw%3ADoNotOptimizeForBrowser%3E%0A%20%3C%2Fw%3AWordDocument%3E%0A%3C%2Fxml%3E%3C!%5Bendif%5D%2D%2D%3E--><!--{cke_protected}{C}%3C!%2D%2D%5Bif%20gte%20mso%209%5D%3E%3Cxml%3E%0A%20%3Cw%3ALatentStyles%20DefLockedState%3D%22false%22%20LatentStyleCount%3D%22156%22%3E%0A%20%3C%2Fw%3ALatentStyles%3E%0A%3C%2Fxml%3E%3C!%5Bendif%5D%2D%2D%3E--><!--{cke_protected}{C}%3C!%2D%2D%5Bif%20gte%20mso%2021%5D%3E%0A%3Cstyle%3E%0A%20%2F*%20Style%20Definitions%20*%2F%0A%20table.MsoNormalTable%0A%09%7Bmso-style-name%3A%E6%99%AE%E9%80%9A%E8%A1%A8%E6%A0%BC%3B%0A%09mso-tstyle-rowband-size%3A0%3B%0A%09mso-tstyle-colband-size%3A0%3B%0A%09mso-style-noshow%3Ayes%3B%0A%09mso-style-parent%3A%22%22%3B%0A%09mso-padding-alt%3A0cm%205.4pt%200cm%205.4pt%3B%0A%09mso-para-margin%3A0cm%3B%0A%09mso-para-margin-bottom%3A.0001pt%3B%0A%09mso-pagination%3Awidow-orphan%3B%0A%09font-size%3A10.0pt%3B%0A%09font-family%3A%22Times%20New%20Roman%22%3B%0A%09mso-fareast-font-family%3A%22Times%20New%20Roman%22%3B%0A%09mso-ansi-language%3A%230400%3B%0A%09mso-fareast-language%3A%230400%3B%0A%09mso-bidi-language%3A%230400%3B%7D%0A%3C%2Fstyle%3E%0A%3C!%5Bendif%5D%2D%2D%3E-->飞机的航程；<!--{cke_protected}{C}%3C!%2D%2D%5Bif%20gte%20mso%209%5D%3E%3Cxml%3E%0A%20%3Cw%3AWordDocument%3E%0A%20%20%3Cw%3AView%3ENormal%3C%2Fw%3AView%3E%0A%20%20%3Cw%3AZoom%3E0%3C%2Fw%3AZoom%3E%0A%20%20%3Cw%3APunctuationKerning%3E%3C%2Fw%3APunctuationKerning%3E%0A%20%20%3Cw%3ADrawingGridVerticalSpacing%3E7.8%20%E7%A3%85%3C%2Fw%3ADrawingGridVerticalSpacing%3E%0A%20%20%3Cw%3ADisplayHorizontalDrawingGridEvery%3E0%3C%2Fw%3ADisplayHorizontalDrawingGridEvery%3E%0A%20%20%3Cw%3ADisplayVerticalDrawingGridEvery%3E2%3C%2Fw%3ADisplayVerticalDrawingGridEvery%3E%0A%20%20%3Cw%3AValidateAgainstSchemas%3E%3C%2Fw%3AValidateAgainstSchemas%3E%0A%20%25/12最新教育资料优选0%3Cw%3ASaveIfXMLInvalid%3Efalse%3C%2Fw%3ASaveIfXMLInvalid%3E%0A%20%20%3Cw%3AIgnoreMixedContent%3Efalse%3C%2Fw%3AIgnoreMixedContent%3E%0A%20%20%3Cw%3AAlwaysShowPlaceholderText%3Efalse%3C%2Fw%3AAlwaysShowPlaceholderText%3E%0A%20%20%3Cw%3ACompatibility%3E%0A%20%20%20%3Cw%3ASpaceForUL%3E%3C%2Fw%3ASpaceForUL%3E%0A%20%20%20%3Cw%3ABalanceSingleByteDoubleByteWidth%3E%3C%2Fw%3ABalanceSingleByteDoubleByteWidth%3E%0A%20%20%20%3Cw%3ADoNotLeaveBackslashAlone%3E%3C%2Fw%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