题干

如图所示,质量为M、长为L的木板置于光滑的水平面上,一质量为m的滑块放置在木板左端,滑块与木板间滑动摩擦力大小为f.现用一水平恒力F作用在滑块上,当滑块运动到木板右端时,木板在地面上移动的距离为s.

下列说法正确的是(   )

A:上述过程中,滑块克服摩擦力做功为f(L+s)

B:其他条件不变的情况下,M越大,s越小

C:其他条件不变的情况下,F越大,滑块到达木板右端所用时间越长

D:其他条件不变的情况下,F越大,滑块与木板间产生的热量越多

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答案(点此获取答案解析)

A,B

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    Ways to Host an Eco-Friendly Cookout

    Eating in the open air may feel eco-friendly, but outdoor dining can result in unnecessary waste if you aren't careful.____If you keep that in mind throughout your preparations, you'll be off to a good start.

Reduce, Reuse, Recycle

    Skip the paper invitations and use online services like Email, or Facebook events____This way you'll avoid ending up with five different potato salads that go uneaten. Make it easy for guests to sort garbage by positioning different trashcans in a central location: one for kitchen garbage, one for recyclables, and one for non-recyclables.

Stop Using Plastic

    Plastic is a leading cause of litter and isn't easy to recycle. To make sure your cookout eco-friendly, consider some other options for making your cookout stand out. Use recycled jars as glasses. They're also far less breakable than regular glasses____ If guests know which glass is theirs, they don't need to reach for another one, which cuts down on the cleanup you'll be doing.

____

    Wherever possible, shop for local produce and goods to serve your guests. This will reduce your carbon footprint and help support your local economy. Buy produce and meats at your local farmers' market. Look for organic, but favor local over organic if you have to make a choice.

Use Renewable Light Sources

    ____ As the sun goes down, illuminate your party space with LED lighting and solar- powered decorations. Invest in some citronella (香茅精油) candles and torches to help drive away insects naturally.

A. Support Global Economy

B. Think Globally, Shop Locally

C. Ask guests to bring glasses of their own

D. Keep track of what everyone is bringing ahead of time

E. Save on energy by hosting your party during the daylight hours

F. One of the keys to being green is to reduce waste wherever possible

G. Put up some labels to the jars so people can write their names on them