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一个质量为m的物体,从倾角为θ,高为h的斜面上端A点,由静止开始下滑,到B点时的速度为v,然后又在水平面上滑行s位移后停止在C点,求:

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    China is a big country, and there is no simple answer to the question “When is the best time to visit China? ” There are two best times to visit China, depending on your preference.

    October

    Things to do: hike on the Great Wall, photography tour

    Places to visit: Beijing, Xi'an, Shanghai, Guilin, Jiuzhaigou, Chengdu

The best time to go to China is early autumn (October).

    Most of China has warm temperatures, and the summer rains have stopped (apart from around HongKong and Sanya) so it's pretty dry. The autumnn colours are also amazing. It is quiet at tourist attractions for most of the month, as the summer holiday travel crowds have gone. But try to avoid October 1st -7th, which is the Chinese National Day holiday, as attractions, transport and hotels are packed with Chinese tourists and prices go up a lot.

    Late Spring (April to May)

    Things to do: appreciate flowers, Li River cruise, ethnic festivals

    Places to visit: Beijing, Xi'an, Guilin, Huangshan, GuiZhou, Zhangjiajie

    The second-best time to travel to China is probably in April and May, when the flowers are in bloom and the temperatures are warming up. In late spring, temperatures across China are getting into the 20s (℃), except the extreme northwest and northeast. While the North of China is still dry, the summer rains have already begun in the South. This could actually improve the view in the form of mountain fog in mountainous areas like the Li River and the Yellow Mountains.

    Ethnic festivals in GuiZhou are concentrated in April and May, such as the Sisters' Meal Festival. If you are interested in Miao and Dong ethnic cultures, this is a good time to visit.

    Travel prices are average: cheaper than June to October, but more expensive than the lower season from November to March.