问题
不定项选择
一质量为m的小球,从离地面高H处由静止开始自由下落。不计空气阻力,以地面为零势能面,当下落到离地面的高度为h时,小球的机械能为[ ]
A.
B.
C.
D.
答案
答案:A
一质量为m的小球,从离地面高H处由静止开始自由下落。不计空气阻力,以地面为零势能面,当下落到离地面的高度为h时,小球的机械能为[ ]
A.
B.
C.
D.
答案:A
![]() Experience the newly opened Grand Canyon(大峡谷)West Skywalk in Colorado.Departing from Grand Canyon’s South Rim by Airplane to Grand Canyon’s West Rim,you will land and take a ground tour to the Skywalk!Walk on air for 70 feet over the edge of Grand Canyon West. This Skywalk has been open since March 28,2007.Daily visitorship to the Skywalk has been over 4000 people.Please be patient to enjoy your moment on the Skywalk. After you have experienced the one and only Grand Canyon Skywalk Glass Bridge,you will return to the Grand Canyon West Airport and take your Airplane for a flight back to the South Rim of the Canyon.This is a tour never to be forgotten as you will have walked on air over the Grand Canyon. Tour Itinerary(行程)
![]() 小题3:The Grand Canyon Skywalk Bridge is made of glass because_______.
A.South Rim→Guano Point→West Airport→Eagle Point→West Airport→South Rim B.South Rim→West Airport→Guano Point→Eagle Point→West Airport→South Rim C.South Rim→West Airport→Eagle Point→Guano Point→West Airport→South Rim South Rim→West Airport→Eagle Point→West Airport→Guano Point→South Rim |