本课配套习题挑战模式1/5
如图所示,一直杆可绕O点转动,杠杆下端挂一重物,为了提高重物,用一个始终跟杠杆垂直的力使杠杆由竖直位置慢慢转到水平位置,在这个过程中直杆( )
A: 始终是省力杠杆 |
B: 始终是费力杠杆 |
C: 先是省力的,后是费力的 |
D: 先是费力的,后是省力的 |
- 提示1:PHA+56Gu5a6a5piv55yB5Yqb6L+Y5piv6LS55Yqb77yM6ZyA6KaB5Yik5patTDxzdWI+QTwvc3ViPuS4jkw8c3ViPueJqTwvc3ViPuWkp+Wwjzxicj48L3A+
- 提示2:PHA+TDxzdWI+54mpPC9zdWI+LuacgOWIneaYrzDvvIzmnIDlkI7mmK/mnaDmnaDplb/luqbjgII8L3A+
- 提示3:PHA+TDxzdWI+QTwvc3ViPuWFiOaYr+Wkp+S6jkw8c3ViPueJqTwvc3ViPu+8jOacgOWQjuS6jkw8c3ViPueJqTwvc3ViPuOAgjwvcD4=
- 答案:Qw==
PGRpdj7nlLHlm77lj6/nn6XliqjliptGPHN1Yj4xPC9zdWI+55qE5Yqb6IeC5aeL57uI5L+d5oyB5LiN5Y+Y77yM54mp5L2T55qE6YeN5YqbR+Wni+e7iOWkp+Wwj+S4jeWPmO+8jOWcqOadoOadhuS7juerluebtOS9jee9ruWQkeawtOW5s+S9jee9rui9rOWKqOeahOi/h+eoi+S4re+8jOmHjeWKm+eahOWKm+iHgumAkOa4kOWinuWkp++8jOWcqEw8c3ViPueJqTwvc3ViPu+8nEw8c3ViPkE8L3N1Yj7kuYvliY3mnaDmnYbmmK/nnIHlipvmnaDmnYbvvIzlnKhMPHN1Yj7niak8L3N1Yj7vvJ5MPHN1Yj5BPC9zdWI+5LmL5ZCO77yM5p2g5p2G5Y+Y5Li66LS55Yqb5p2g5p2GLjxicj48L2Rpdj4=
本课配套习题挑战模式2/5
均匀木条AOB,形状如图,已知AO=OB,在O点系一线悬挂起来,使AO段处于水平后放手,放手后( )
A: 木条保持静止状态 |
B: 木条A端下降 |
C: 木条B端下降 |
D: 条件不足,无法判断 |
- 提示1:PHA+5Yik5pat5ZOq56uv5LiL6ZmN55qE5pa55rOV5piv5q+U6L6D5Yqo5Yqb5LmY5Lul5Yqo5Yqb6IeC5LiO6Zi75Yqb5LmY5Lul6Zi75Yqb6IeC5aSn5bCP5YWz57O7PC9wPg==
- 提示2:PHA+5bem5Y+z6ZW/5bqm55u45ZCM77yM5LiU5Z2H5YyA77yM5omA5Lul5bem5Y+z6YeN5Yqb5LiA5qC377yM5Y+q6KaB5Yik5pat5Yqb6IeC6ZW/55+t5Y2z5Y+vPC9wPg==
- 提示3:PHA+T0HmrrXlipvoh4Lplb/vvIzmiYDku6VPQeauteS4i+mZjTxicj48L3A+
- 答案:Qg==
PGRpdj7nlLHkuo7pkqLnrYvnspfnu4blnYfljIDvvIzkuJRBTz1PQu+8jOWboOatpE9B44CBT0LmrrXnmoTph43lipvnm7jlkIzvvIzljbNHPHN1Yj5BPC9zdWI+PUc8c3ViPkI8L3N1Yj7vvJs8aW1nIHNyYz0iaHR0cHM6Ly9wMS5xaW5nZ3VvLmNvbS9HMS9NMDAvMjMvNzcvckJBQ0UxTU1aTWZ5WmNvMUFBQVhrU2kwSzRZMDUxLnBuZyIgZGF0YS1ja2Utc2F2ZWQtc3JjPSJodHRwczovL3AxLnFpbmdndW8uY29tL0cxL00wMC8yMy83Ny9yQkFDRTFNTVpNZnlaY28xQUFBWGtTaTBLNFkwNTEucG5nIiBhbHQ9IumdkuaenOWtpumZoiIgaGVpZ2h0PSI4NCIgd2lkdGg9Ijg2Ij48YnI+55Sx5Y+z5Zu+55+l77yaRzxzdWI+QTwvc3ViPueahOWKm+iHgkw8c3ViPkE8L3N1Yj7opoHlpKfkuo5HPHN1Yj5CPC9zdWI+55qE5Yqb6IeCTDxzdWI+Qjwvc3ViPu+8jOWImeacie+8mjxicj5HPHN1Yj5BPC9zdWI+4oCiTDxzdWI+QTwvc3ViPu+8nkc8c3ViPkI8L3N1Yj7igKJMPHN1Yj5CPC9zdWI+77yM5Zug5q2k5p2g5p2G5rK/RzxzdWI+QTwvc3ViPueahOaWueWQkei9rOWKqO+8jOWNs0Hnq6/kuIvmsokuPC9kaXY+
本课配套习题挑战模式3/5
如图所示,OA是轻质杠杆,杠杆中间悬挂有一重物G,A端自始至终受到一个水平方向拉力F的作用,当将杠杆慢慢绕逆时针方向转动的过程中,关于力F的说法正确的是( )
A: 力F变大,F力臂变大 |
B: 力F变大,F力臂变小 |
C: 力F变小,F力臂变小 |
D: 力F变小,F力臂变大 |
- 提示1:PHA+6aaW5YWI5Y+v5Lul5Yik5pat55qE5pivRueahOWKm+iHgjwvcD4=
- 提示2:PHA+5oOz5Yik5patRuWPmOWMlu+8jOmcgOimgeefpemBk0dMPHN1Yj5HPC9zdWI+5Y+Y5YyW5oOF5Ya1PC9wPg==
- 提示3:PHA+6YCa6L+HRkw8c3ViPkY8L3N1Yj49R0w8c3ViPkc8L3N1Yj7liKTmlq1G5Y+Y5YyW5oOF5Ya1PC9wPg==
- 答案:Qg==
PGRpdj7moLnmja7mnaDmnYblubPooaHmnaHku7bliqjlipvDl+WKqOWKm+iHgj3pmLvlipvDl+mYu+WKm+iHgu+8jOWcqOWKm0bkvb/nm7TmnYbku47nq5bnm7TkvY3nva7mhaLmhaLmiqzotbfliLDmsLTlubPkvY3nva7nmoTov4fnqIvkuK3vvIzph43niannmoTph43lipvkuI3lj5jkvYblipvoh4Llj5jlpKfvvIxG55qE5Yqb6IeC5Y+Y5bCP77yM5omA5LulRuS4gOebtOWcqOWinuWkpzwvZGl2Pg==
本课配套习题挑战模式4/5
如图所示,整个装置处于静止状态,当F以B点为轴转从BM方向转向BN(BN⊥OB)方向的过程中,下列说法正确的是( )
A: F逐渐变小 |
B: F逐渐变大 |
C: 先变大后变小 |
D: 先变小后变大 |
- 提示1:PHA+5om+5Yiw5bmz6KGh5pa556iLPC9wPg==
- 提示2:PHA+5om+5Yiw5LiN5Y+Y55qE6YeP5ZKM5Y+Y5YyW55qE6YePPC9wPg==
- 提示3:PHA+6YCa6L+H5Y+Y5YyW5oOF5Ya15Yik5pat5Yqb55qE5Y+Y5YyWPC9wPg==
- 答案:QQ==
PGRpdj7ku47mlK/ngrnlkJHlipvnmoTkvZznlKjnur/kvZzlnoLnur/vvIzlnoLnur/mrrXnmoTplb/luqbljbPlipvoh4LvvJs8YnI+55Sx5p2g5p2G5bmz6KGh5p2h5Lu25Yqo5Yqbw5fliqjlipvoh4I96Zi75Yqbw5fpmLvlipvoh4Llj6/nn6XvvIw8YnI+5Zyo6Zi75Yqb5LiO6Zi75Yqb6IeC5LiN5Y+Y55qE5oOF5Ya15LiL77yM5Yqo5Yqb6IeC6LaK5aSn77yM5Yqo5Yqb6LaK5bCP77yMPGJyPuagueaNruWbvuekuuWIpOaWreWKqOWKm+iHgueahOWPmOWMluaDheWGte+8jOeEtuWQjuWIpOaWreWKqOWKm+eahOWPmOWMluaDheWGtS48YnI+PC9kaXY+PGRpdj7ku45CTeWIsEJO55qE6L+H56iL5Lit5Yqb6IeC6YCQ5riQ5Y+Y5aSn77yM5bm25LiU6L6+5Yiw5pyA5aSn5Yqb6IeC44CC5q2k6L+H56iL5Yqb6YCQ5riQ5YeP5bCP44CCPGJyPjwvZGl2Pg==
本课配套习题挑战模式5/5
如图所示是一根重为G的均匀木棒OA,能以支点0自由转动,现用力FC作用于木棒的A端,使木棒OA在水平位置上保持平衡. 当力F由FC方向逐渐转到FB时,力的大小变化为( )
A: 一直在减小 |
B: 保持不变 |
C: 先减小后增大 |
D: 先增大后减小 |
- 提示1:PHA+5om+5Yiw5bmz6KGh5pa556iLPC9wPg==
- 提示2:PHA+5om+5Yiw5LiN5Y+Y55qE6YeP5ZKM5Y+Y5YyW55qE6YePPC9wPg==
- 提示3:PHA+6YCa6L+H5Y+Y5YyW5oOF5Ya15Yik5pat5Yqb55qE5Y+Y5YyWPC9wPg==
- 答案:Qw==
PGRpdj7mnaDmnYbmsLTlubPvvIzmnaDmnYbnmoTph43lipvmmK/pmLvlipvvvIzpmLvliptH5LiO6Zi75Yqb6IeCTDxzdWI+Rzwvc3ViPuS4jeWPmO+8jDxicj7nlLHlm77npLrlj6/nn6XvvIzliqjlipvnlLFGPHN1Yj5DPC9zdWI+5Y+Y5Li6RjxzdWI+Qjwvc3ViPuaXtu+8jOWKqOWKm+iHgkzlhYjlj5jlpKflkI7lj5jlsI/vvIw8YnI+55Sx5p2g5p2G5bmz6KGh5p2h5Lu25b6X77yaR8OXTDxzdWI+Rzwvc3ViPj1Gw5dM77yM5omA5Lul5Yqo5Yqb5YWI5Y+Y5bCP5ZCO5Y+Y5aSnPC9kaXY+