(15分)汽车发动机的功率为60 kW，汽车的质量为4 t，当它行驶在坡
度为0.02(sinα＝0.02)的长直公路上时，如图10所示，所受摩擦阻力为车
重的0.1倍(g＝10 m/s2)，求： (1)汽车所能达到的最大速度vm；
(2)若汽车从静止开始以0.6 m/s2的加速度做匀加速直线运动，则此过程能维持多长时间？
(3)当汽车匀加速行驶的速度达到最大值时，汽车做功多少？
(1)12.5 m/s (2)13.9 s (3)4.16×105 J
| The conception of God and nature and of the relation of man to both provided the 18th- century philosophers with their faith in the worth and dignity of the individual man and the efficacy of human reason. The 18th century was the moment in history when men experienced the first flush and freshness of the idea that man is master of his own fate; the moment in history, also, when this emancipating idea, not yet brought to the harsh test of experience, could be accepted with unclouded optimism. Never had the nature seemed less mysterious, more simply constructed, more open and visible and eager to yield its secrets to common-sense questions. Never had the nature of man seemed less perverse, or the intelligence and will of men more pliable (yielding) to rational persuasion. Never had social and political evils seemed so wholly the result of ignorance and superstition, or so easily corrected by the spread of knowledge and the construction of social institutions on a rational plan. The first task of political science was to discover the natural rights of man, the second to devise the form of government best suited to secure them. And for accomplishing this high task, for creating and maintaining a society founded on justice and equality, the essential freedom was freedom of the mind. |
According to the last sentence of Paragraph 2, all the following statements can be true EXCEPT ______ ．
A．Social evils may lead to human beliefs of monsters
B．Political problems can be solved through education
C．The building of a hospital may help to ease social disorder
D．Education can help to cure both social and political problems