问题 计算题

(8分)如图所示为利用阻拦系统让舰载机在航母的飞行甲板上快速停止的原理示意图.飞机着舰并成功钩住阻拦索后,飞机的动力系统立即关闭,阻拦系统通过阻拦索对飞机施加一作用力,使飞机在甲板上短距离滑行后停止。设飞机着舰时恰好钩住阻拦索中间位置,经过图示位置时开始沿水平方向做匀减速直线运动,经过时间t后速度减小到零。在图示位置时阻拦索与两个定滑轮(大小不计)连线的夹角为θ1,速度减小到零时阻拦索与两个定滑轮连线的夹角为θ2,已知飞机的质量为m,飞机受到甲板和空气的阻力为恒力f,两个定滑轮之间的距离为L。求图示位置阻拦索的张力大小。

答案

题目分析:设飞机与两滑轮连线距离为x,则          1分

          1分

飞机减速位移       1分

设绳的拉力为T,飞机加速度为a,则          2分

        1分

由以上各式得:        2分

问答题

Turkey’s Bodrum peninsula is different. The tourist boom in this part of the world (1) turned some small villages into resorts yet left neighbouring beaches undisturbed, making it quite (2) southern France or the Spanish Coasts where few stretches of coastline are undevelopeD.
The (3) for this happy set of circumstances is simple. For thousands of years, travel here (4) easier by boat than by lanD.So when mass tourism arrived in the (5) 1980s, there was no coast road for ribbon development to follow. So the peninsula, just (6) hour from Bodrum airport, has not become one long littoral of resort.
The building (7) new hotels has mainly been confined to places easily reached by then relatively (8) roads. Such ease of access has made Gumbet, near Bodrum, a busy resort, while the little fishing village of Gumusluk, 12 miles further west and only recently reachable by (9) , remains tranquil and undisturbeD.
It’s worth thinking carefully about location when planning a family (10) on the peninsulA.Choose a place that is centrally located, preferably out of earshot (11) Bodrum town’s "lively"—which means nosy—nightlife, and you can then use (12) area’s comfortably small scale to your advantage. Today’s new roads mean most places can (13) reached in under an hour by taxi or the ubiquitous dolmus-minibus.
The (14) of facilities at the Tamarisk Beach Hotel near the small village of Ortakent makes (15) a good base. The family-run hotel—rooms and suites are in two-storey buildings (16) by palm trees and flowers in terracotta pots—sits above its own sandy (17) beach, shaded by tamarisk trees and sheltered by nearby islands.
The hotel is (18) child-friendly, too. Children, from infants up to young teenagers, can take part in a (19) of games and activities that include tuition in windsurfing, dinghy (20) catamaran sailing.

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