【单选题】等直杆的受力情况如图所示,则杆中的最大轴力和最小轴力分别为( )。
【简答题】设一个随机过程ζ(t)可表示成ζ(t)=2cos(2πt+θ),式中θ是一个离散随机变量,且P(θ=0)=1/2、P(θ=π/2)=1/2,试求Eζ(1)及R ζ (0,1)。
【单选题】?Read the following article about LG's success in India and the questions on the opposite page. ?For each question 15-20, mark one letter (A, B, C or D ) on your Answer Sheet for the answer you choose...
A.
become financially aggressive.
B.
win championship of marketing.
C.
achieve success in their careers.
D.
alter their way of doing business.
【单选题】Which of the following is NOT a fault that may slow the reader's speed?
A.
Some people read aloud.
B.
Some people follow the line with a finger or a pen.
C.
Some people do not exert themselves to read faster, or slow down as needed.
【简答题】如图所示,AB为倾角θ=37°的斜面轨道,轨道AC部分光滑,CB部分粗糙,一质量m=2 kg的小物块与斜面BC间的动摩擦因数μ=0.25;BP为圆心角等于143°,半径R=0.5 m的竖直光滑圆弧形轨道,两轨道相切于B点,P、O两点在同一竖直线上;轻弹簧一端固定在A点,另一端在斜面上C点处,已知sin 37°=0.6,cos 37°=0.8,g取10 m/s 2 。 (1)若小物块静止在弹簧上端,...
【单选题】用稀酸稀碱处理后得到的粗纤维中不含有( )
【多选题】企业选择申报方式时应该考虑的因素有( )
【单选题】圆C的方程为(x-2) 2 +y 2 =4,圆M的方程为(x-2-5sinθ) 2 +(y-5cosθ) 2 =1(θ∈R),过圆C上任意一点P作圆M的两条切线PE、PF,切点分别为E、F,则 PE ? PF 的最小值是( )
【简答题】设随机过程ξ (t) 可表示成 ξ (t) = 2cos(2 π t+ θ ) 式中θ是一个 离散随机变量 ,且 P( θ =0)=1/2 、 P( θ = π /2)=1/2 ,试求 E[ ξ (1)] 及 R ξ (0,1) 。