A:115
B:25
C:715
D:815
如图为亚洲区域示意图,读图完成下列问题.
Sydney TowerAddress: 100 Market St, SydneyPhone: 02 9333 9222Fax: 02 9333 9203Open time: 9:00 a.m. t0 10:30 p.m. (Saturdays to 11:30 pm)Ticket: $60 (for an adult) $30 (for a child)Website: www.sydneytower.com.auHow to get there: train to Town Hall Station and a short walk along Market StreetHow to book tickets: by phone/fax or through the webAttractions: Sydney’s best views are just the beginning! Sydney Tower takes you to the highest pointabove Sydney for exciting 360° view of our beautiful city.
为使飞机在开始滑行时就有一定的初速度,航空母舰装有弹射装置,然后在飞机发动机产生动力作用下做匀加速直线运动最后起飞.某型号的飞机经弹射系统作用后,具有144km/h的初速度,但起飞的速度须达到180km/h.该飞机提供的牵引力为1.32×15N,起飞质量为2.7×104kg,若飞机在跑道上匀加速100m.
物体以一定的初速度从斜面底端A点冲上固定的光滑斜面,斜面总长度为l,到达斜面最高点C时速度恰好为零,如图,已知物体运动到距斜面底端处的B点时,所用时间为t,则物体从B滑到C所用的时间为____.
①写字的笔杆握笔处凹凸不平;②厨房的菜刀刀刃磨得很薄;
③装订试卷时用力按压订书机;④运动鞋底花纹做的很深.
其中主要目的为了增大压强的是____ ,增大摩擦的是____ .(填写序号)