One study conducted by a psychologist (121) of interviewing workers before and after the installation of a robot. The robot was used to control a matching process of stamping and assembling metal parts. Prior to installation, much of the work done by skilled machinists. After installation, the robot did the work, but the workers controlled the robot through the robot through a control panel. The results of the study indicated that the workers praised the robot (122) eliminating the physical labor and fatigue (123) the manual operation, but complained of more and continued stress. Prior to installation of the robot, there was time for talking or short periods of relaxation between jobs. Now, however, because of the speed of the robot, there was a need for constant scanning and monitoring of the operation (124) performed by the robot has the installation of the robot created a better work environment Has the change from physical labor to mental stress resulted in an improved (125) of life Much additional research is necessary.
A．Of
B．consisted
C．for
D．being
，斜面底端固定一个与斜面垂直的挡板，一木板A被在斜面上，其下端离地面高为H，上端放着一个小物块B，如图所示。木板和物块的质量均为m,相互间最大静摩擦力等于滑动摩擦力
（A > 1)，把它们由静止释放，木板与挡板发生碰撞时，时间极短，无动能损失，而物块不会与挡板发生碰撞.求：
