2024年高中物理新教材同步講義選修第一冊(cè)講義第4章　專題強(qiáng)化　板塊問(wèn)題

專題強(qiáng)化板塊問(wèn)題[學(xué)習(xí)目標(biāo)]1.能正確運(yùn)用牛頓運(yùn)動(dòng)定律處理水平面上的滑塊—木板問(wèn)題(重難點(diǎn))。2.熟練應(yīng)用牛頓運(yùn)動(dòng)定律解決實(shí)際問(wèn)題(重點(diǎn))。一、地面光滑的板塊問(wèn)題1．如圖，木板B、物塊A的質(zhì)量分別為M和m，不計(jì)物塊大小，開(kāi)始A、B均靜止，現(xiàn)使A以v0從B的左端開(kāi)始運(yùn)動(dòng)。已知A、B間動(dòng)摩擦因數(shù)為μ，地面光滑。(1)分析A剛滑上B時(shí)，A、B的加速度大?。?2)分析A、B各自的運(yùn)動(dòng)情況？________________________________________________________________________________________________________________________________________________2．若A的質(zhì)量m＝1kg，B的質(zhì)量M＝4kg，A、B間動(dòng)摩擦因數(shù)μ＝0.2，地面光滑，A、B開(kāi)始均靜止，現(xiàn)對(duì)A施加向右的水平恒力F，試分析在以下兩種情況下A、B的可能運(yùn)動(dòng)情況。(1)F＝5N；(2)F＝2N。________________________________________________________________________________________________________________________________________________例1如圖所示，光滑水平桌面上有一質(zhì)量M為2kg的長(zhǎng)度足夠長(zhǎng)的長(zhǎng)木板，一質(zhì)量m為1kg的小物塊從長(zhǎng)木板的左端以大小為3m/s的初速度v0滑上長(zhǎng)木板，物塊與長(zhǎng)木板間的動(dòng)摩擦因數(shù)μ為0.2，重力加速度g＝10m/s2。求：(1)小物塊剛滑上木板時(shí)，小物塊和木板的加速度大??；(2)小物塊的最終速度的大小；(3)小物塊最終距長(zhǎng)木板左端的距離。________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________例2如圖所示，在光滑的水平地面上有一個(gè)長(zhǎng)為L(zhǎng)＝0.64m、質(zhì)量為mA＝4kg的木板A，在木板的左端有一個(gè)大小不計(jì)、質(zhì)量為mB＝2kg的小物體B，A、B間的動(dòng)摩擦因數(shù)為μ＝0.2，求：(g取10m/s2)(1)當(dāng)對(duì)B施加水平向右的力F＝4N時(shí)，A、B加速度各為多大？(2)當(dāng)F＝10N時(shí)，A、B加速度各為多大？(3)當(dāng)F＝10N時(shí)，經(jīng)過(guò)多長(zhǎng)時(shí)間可將B從木板A的左端拉到右端？________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________二、地面粗糙的板塊問(wèn)題1．如圖所示，粗糙水平地面上，靜止放置質(zhì)量為M的長(zhǎng)木板，一小木塊質(zhì)量為m，以速度v0沖上木板，若木板與地面間動(dòng)摩擦因數(shù)為μ2，木塊與木板間動(dòng)摩擦因數(shù)為μ1。(1)試分析木板相對(duì)地面發(fā)生滑動(dòng)的條件；(2)若木板相對(duì)地面發(fā)生了滑動(dòng)，且木塊能從木板上滑下，分析在木板、木塊運(yùn)動(dòng)的過(guò)程中各自的加速度大小。________________________________________________________________________________________________________________________________________________________________________________________________________________________2.如圖所示，木板A、木塊B靜止在粗糙水平面上，質(zhì)量分別為M、m，外力F作用在木塊上，逐漸增大F。則：(1)木板一定會(huì)相對(duì)水平地面滑動(dòng)嗎？(2)若能發(fā)生相對(duì)滑動(dòng)，A、B間動(dòng)摩擦因數(shù)為μ1，A與地面間動(dòng)摩擦因數(shù)為μ2，分析A、B加速度的大?。縚_______________________________________________________________________________________________________________________________________________________________________________________________________________________例3如圖所示，物塊A、木板B的質(zhì)量均為m＝10kg，不計(jì)A的大小，木板B長(zhǎng)L＝3m。開(kāi)始時(shí)A、B均靜止?，F(xiàn)使A以水平初速度v0從B的最左端開(kāi)始運(yùn)動(dòng)。已知A與B、B與水平面之間的動(dòng)摩擦因數(shù)分別為μ1＝0.3和μ2＝0.1，g取10m/s2。(1)發(fā)生相對(duì)滑動(dòng)時(shí)，A、B的加速度各是多大？(2)若A剛好沒(méi)有從B上滑下來(lái)，則A的初速度v0為多大？________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________例4如圖所示，質(zhì)量M＝1kg、長(zhǎng)L＝4m的木板靜止在粗糙的水平地面上，木板與地面間的動(dòng)摩擦因數(shù)μ1＝0.1，在木板的左端放置一個(gè)質(zhì)量m＝1kg、大小可以忽略的鐵塊，鐵塊與木板上表面間的動(dòng)摩擦因數(shù)μ2＝0.4，某時(shí)刻起在鐵塊上施加一個(gè)水平向右的恒力F＝8N，g取10m/s2。(1)求施加恒力F后鐵塊和木板的加速度大?。?2)鐵塊經(jīng)多長(zhǎng)時(shí)間到達(dá)木板的最右端，求此時(shí)木板的速度大小。(3)當(dāng)鐵塊運(yùn)動(dòng)到木板最右端時(shí)，把鐵塊拿走，木板還能繼續(xù)滑行的距離。___________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________