问题 选择题

在大型游乐场里,小王乘坐如图所示匀速转动的“摩天轮”,正在向最高点运动,对此过程,下列说法正确的是 

A.小王的重力势能保持不变

B.小王的动能保持不变

C.小王的机械能守恒

D.小王的机械能减少

答案

答案:B

“摩天轮”匀速转动,小王动能不变,向最高点运动,重力势能增加,机械能增加,B对。

选择题
阅读理解

阅读理解.

     Homestay provides English language students with the opportunity to speak English

outside the classroom and the experience of being part of a British home.

     What to Expect

     The host will provide accommodation and meals.Rooms will be cleaned and bedcovers

changed at least once a week.You will be given the house key and the host is there to

offer help and advice as well as to take an interest in your physical and mental health.

     Accommodation Zones

     Homestays are located in London mainly in Zones 2, 3 and 4 of the transport system.

Most hosts do not live in the town centre as much of central London is commercial and

not residential(居住的).Zones 3 and 4 often offer larger accommodation in a less

crowded area.It is very convenient to travel in London by Underground.

     Meal Plans Available

     ◇Continental Breakfast

     ◇Breakfast and Dinner

     ◇Breakfast, Packed Lunch and Dinner

     It's important to note that few English families still provide a traditional cooked

breakfast.Your accommodation includes Continental Breakfast which normally consists

of fruit juice,cereal (谷物类食品), bread and tea or coffee.Cheese, fruit and cold meat

are not normally part of a Continental Breakfast in England.Dinners usually consist of meat

or fish with vegetables followed by dessert, fruit and coffee.

     Friends

     If you wish to invite a friend over to visit, you must first ask your host's permission.You

have no right to entertain friends in a family home as some families feel it is an invasion of

their privacy.

     SelfCatering Accommodation in Private Homes

     Accommodation on a roomonly basis includes shared kitchen and bathroom facilities

and often a main living room.This kind of accommodation offers an independent lifestyle

and is more suitable for the longstay student.However, it does not provide the same family

atmosphere as an ordinary homestay and may not benefit those who need to practise English

at home quite as much.

1.The passage is probably written for ________.

A.hosts willing to receive foreign students

B.foreigners hoping to build British culture

C.travellers planning to visit families in London

D.English learners applying to live in English homes

2.Which of the following will the host provide?

A.Room cleaning.B.Medical care.

C.Free transport.D.Physical training.

3.What can be inferred from Paragraph 3?

A.Zone 4 is more crowded than Zone 2.

B.The business centre of London is in Zone 1.

C.Hosts dislike travelling to the city centre.

D.Accommodation in the city centre is not provided.

4.According to the passage, what does Continental Breakfast include?

A.Dessert and coffee.

B.Fruit and vegetables.

C.Bread and fruit juice.

D.Cereal and cold meat.