问题
计算题
一物体做匀加速直线运动,途中由A经B到C历时4s,前2s从A到B和后2s从B到C的位移分别为24m和32m。求:
(1)物体运动的加速度为多少?
(2)物体在A点和C点的瞬时速度的分别为多少?
答案
(1)a=2m/s2 (2)vA=10m/s,vC=18m/s
一物体做匀加速直线运动,途中由A经B到C历时4s,前2s从A到B和后2s从B到C的位移分别为24m和32m。求:
(1)物体运动的加速度为多少?
(2)物体在A点和C点的瞬时速度的分别为多少?
(1)a=2m/s2 (2)vA=10m/s,vC=18m/s
完形填空 | |||
Mother's Day is celebrated (庆祝) in the USA.It's also a holiday in some 1 countries. It's on the second Sunday in May. It is a day to thank 2 .On that day mothers usually 3 flowers and cards. On the cards,children will write "Thanks,Mum" ,"To the best mother in the world", "Best wishes for Mother's Day" and so on. Where does the idea for the holiday 4 ?We should thank Miss Anna M. Jarvis. She brought up the idea of having such a day. She lived in West Virginia.Her mother died 5 May 9,1905. She 6 her mother. She wrote letters to some important persons. In her letters she asked them to decide a day for 7 mothers. Then Mother's Day was made on the second Sunday in May by the USA 8 1913. On Mother's Day,children give presents to their mothers, 9 the whole family go out and try to do something 10 for their mothers to make them happy. | |||
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