题干

如图所示,在杠杆OA上的B点悬挂一重物G,A端用细绳吊在小圆环E上,且细绳AE长等于圆狐CED的半径,此时杠杆恰好成水平状态,A点与圆弧CED的圆心重合,E环从C点沿顺时针方向逐渐滑到D点的过程中,吊绳对A端的作用力大小将(   )

A:保持不变

B:逐渐变大

C:由大变小,再由小变大

D:由小变大,再由大变小

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C

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    Fresh off his MasterChef Junior run, Evan Robinson, who is only 12 years old, is using his kitchen skills to raise money for Puerto Rico. The TV show contestant wanted to offer help after hurricanes(飓风) hit the country last September.

    “I've been seeing, all over the news, people struggling,” Evan said. “They can't get fresh water, electricity; they can't get really anything. I know I'm just a kid, but I think if a lot of people do something, a lot of things will get better.”

    He raises money by baking and taking online orders for homemade empanadas(馅 饼). He started cooking on a recent Friday night. By the next Sunday evening, he had filled orders for 420 empanadas — — roasted chicken, cheeseburger and vegetarian — — getting $18 for six empanadas and $30 for a dozen.

    His mom, Veronica Robinson, helped him send the empanadas around the city. “We've never done anything like this before,” she said. “But it's a great idea, so I want to help him make it work.”

    For Evan's out-of-town friends and supporters, he has set up a crowdfunding(众筹) page. Through it, he's hoping to raise $1, 500 in “virtual (虚 拟 的) empanadas”. This is because he heard on the news that it could take Puerto Rico years, maybe  even 10 years, to recover(复 原) from the hurricanes. And he said, “Fruit pies are up next. And my baking will continue as well.”

    It's a difficult job, especially for a kid with homework and Boy Scouts and friendships to tend to. But he doesn't seem worried.

    “It's what we're supposed to do.” he said. “I'm a human. They're humans. Why shouldn't I help them?”

    Indeed.