问题 多选题

如图所示,绝缘弹簧的下端固定在斜面底端,弹簧与斜面平行,带电小球Q(可视为质点)固定在光滑绝缘斜面上的M点,且在通过弹簧中心的直线ab上.现把与Q大小相同,电性相同的小球P,从直线ab上的N点由静止释放,在小球P与弹簧接触到速度变为零的过程中,以下说法正确的是(  )

A.小球P、小球Q、弹簧、还有地球组成系统的机械能不守恒

B.小球P和弹簧的机械能守恒,且P速度最大时所受弹力与库仑力的合力最大

C.小球P的动能、与地球间重力势能、与小球Q间电势能和弹簧弹性势能的总和不变

D.小球P的速度先增大后减小

答案

解;A、在小球P与弹簧接触到速度变为零的过程中,库仑力做正功,机械能不守恒,故A正确

B、由A分析可知,小球P和弹簧的机械能不守恒,且P速度最大时所受弹力与库仑力的合力也不是最大值,故B错误

C、根据机械能守恒定律知,小球P的动能、与地球间重力势能、与小球Q间电势能和弹簧弹性势能的总和不变,故C正确

D、小球先沿斜面加速向下运动,后减速向下运动,当弹簧压缩量最大时,小球静止,故D正确

故选ACD

阅读理解
 信息匹配。
阅读下列应用文及相关信息,, 并按照要求匹配信息。首先请阅读下列餐馆的信息:
APasta House-new Italian restaurant located in the heart of the city. Simple but delicious inexpensive
meals. Also has a good range of vegetableonly meals. It's always crowded so be ready to order
takeaway or share a table. Open 11 am to midnight.
BA Taste of India-famous for its spicy curries and many southern Indian dishes using chilli. You will
usually be able to find a table during the week but if you're planning to go on the weekend, make sure
you book a table in advance. Open noon to midnight.
CParis Match-this is the finest French restaurant in the city. Wonderful food you can enjoy in luxurious
surrounding. The perfect place to have a romantic meal or impress a business partner, but be prepared
for a large bill. Open noon to 2 am. Booking essential.
DMountain Diner-not fancy but tasty. Excellent Asian and European dishes. Countryside location surrounded by forest. It's at least an hour's drive from the city, so you might want to stay at the nearby Mountain
Hotel, overnight. Open 7 am to 10 pm.
EOwl Cafe-open 24 hours a day, the cafe has a large selection of set breakfast, lunch and dinner meals
for you to choose from, or you can enjoy one of their many delicious snacks and desserts over a cup of
freshly made coffee.
FGreek Bistro-a lively restaurant that serves greatvalue Greek food and has live Greek music played by
a local band. Customers are encouraged to take part in the entertainment, so be ready for a night of loud
fun and laughter. Open 6 pm to 2 am.
以下是五个人的选择要求, 请匹配每个人拟选择的地方:
1. Bill was late getting up today so he hasn't had time to make breakfast. He wants to pick up something
   to eat before he goes to work so he has enough energy to last through to lunch time.
2. Julie works in the city and wants to get some lunch. She doesn't want anything too special so long as it
    is tasty and not too expensive. Julie likes all kinds of food but because she is on a diet she wants to
    avoid anything containing meat.
3. Sally has friends visiting her from outoftown and wants to take them to dinner. She wants to take them
    somewhere they can enjoy the atmosphere and have fun. She is a university student, so she doesn't have
    a lot of money and doesn't like her food too hot.
4. Albert is a businessman who will meet an important European client for a business dinner next week.
    Want to book a table at a quiet restaurant that will impress his guest with both its food and its
     surroundings.
5. Robert is meeting his friend Ben for lunch today (Tuesday) and wants to take him to a nice restaurant.
    Both Robert and Ben enjoy good quality spicy food. Robert doesn't like arranging things in advance so
   he hasn't booked a table.
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