题目

第三节  阅读理解（共20题，每题2分，共40分） President Barack Obama has apologized for a gaffe (失言) in which he described his bowling skills as akin to participants in the Special Olympics, a sports program for people with intellectual disabilities. Obama made the mistake during an interview on Thursday night on “The Tonight Show” with host Jay Leno, the first time a sitting U.S. president had been on the show. Talking about living in the White House, Obama said he had been practicing his bowling in the home’s bowling alley and had scored a 129 out of a possible 300如图所示，一个质量m=2kg的物体，受到与水平方向成37°角斜向上方的拉力F=20N，物体与地面间的动摩擦因数为μ=0.5，（已知sin37°=0.6，cos37°=0.8，g=10m/s2）求：（1）拉力F在2s内对物体所做的功；（2）2s末拉力对物体做功的功率．