问题 选择题

甲、乙两同学沿同一直线推一辆静止在光滑地面上的小车,甲用100N的力向左推,乙用80N的力向右推,则小车受到推力的合力的大小和方向是(  )

A.20N,向右

B.20N,向左

C.180N,向左

D.180N,向右

答案

由题知,二力方向相反,并且水平向左的力大小为100N,水平向右的力大小为80N;所以合力大小为F=F-F=100N-80N=20N,方向向左.

故选B.

实验题
阅读理解

While still in its early stages, welfare reform has already been judged a great success in many states-at least in getting people off welfare. It’s estimated that more than 2 million people have left the rolls since 1994.

In the past four years, welfare rolls in Athens County have been cut in half. But 15 percents of the people who left in the past two years took jobs that paid less than $6 an hour. The resuit: The Athens County poverty rate still remains at more than 30 percent-twice the national average.

For advocates (代言人) for the poor, that’s an indication that much more needs to be done.

“More people are getting jobs, but it’s not making their lives any better,” says Kathy Lairn,a policy analyst at the Center on Budget and policy Priorities in Washington.

A center analysis of US Census data nationwide found that between 1995 and 1996, a greater percentage of single, female-headed households were earning money on their own, but that average income for these households actually went down.

But for many, the fact that poor people are able to support themselves almost as well without government aid as they did with it is in itself a huge victory.  

“Welfare was a poison. It was a toxin(毒素) that was poisoning the family,” says Robert Rector, a welfarereform policy analyst. “The reform is changing the moral climate in lowincome communities. It’s beginning to rebuild the work ethic(道德观), which is much more important.”

Mr. Rector and others argued that once “the habit of dependency is cracked, ”then the country can make other policy changes aimed at improving living standards.

13.From the passage, it can be seen that the auther .      

A.believes the reform has reduced the government’s burden

B.insists that welfare reform is doing little good for the poor

C.is overenthusiastic about the success of welfare reform

D.considers welfare reform to be fundamentally successful

14.Why aren’t people enjoying better lives when they have jobs?

A.Because many families are divorced.        B.Because government aid is now rare.

C.Because their wages are low.               D.Because the cost of living is rising.

15.What is worth noting from the example of Athens County is that .      

A.greater efforts should be made to improve people’s living standards

B.15 percent of the people there have been employed for two years

C.50 percent of the population no longer relies on welfare

D.the living standards of most people are going down

16.From the passage we know that welfare reform aims at_______ .

A.saving welfare funds                       B.rebuilding the work ethics(观念)

C.providing more jobs                        D.cutting government expenses