如图所示，位于光滑固定斜面上的小物块P受到一水平向右的推力F的

搜题请搜索小程序“爱下问搜题”

问题选择题

如图所示，位于光滑固定斜面上的小物块P受到一水平向右的推力F的作用。已知物块P在斜面上静止。现保持F的方向不变，使其减小，但P仍静止，则斜面对P的摩擦力

[ ]

A．一定变小

B．一定变大

C．一定不变

D．可能变小，可能变大

答案

答案：D

听力题

单词拼写（每空一词，每小题1分，满分10分）

小题1:Many _____________ (残疾的) people have worked wonders.

小题2:Annie’s __________(协助) changed Helen from a deaf-blind child into a remarkable writer.

小题3:Sunshine is b___________（有益的） to the health.

小题4:When her husband died, she received many letters and calls of ____________ (同情) .

小题5:The well-known singer was a______________ on the piano by Langlang .

小题6:The ____________ (年度的)death rate in the United States is 11 per100.

小题7:He ____________ (逃离)his village to join the army when he was 17.

小题8:He told the police about the accident as he w____________ it on his way home.

小题9:Education should not be considered to be a ______________(特权) in modern society.

问答题简答题

血痕开展DNA鉴定的最长时限是多少？