问题
计算题
在排球比赛中,扣球手抓住一次机会打了一个“探头球”,已知来球速度为10 m/s,击回的球速度大小为20 m/s,击球时间为0.05s,假设速度方向均为水平方向,求:击球过程中排球的加速度。
答案
解:设排球的初速度方向为正,则由加速度定义得a=m/s2=-600 m/s2,即加速度的大小为600 m/s2,方向与初速度方向相反
在排球比赛中,扣球手抓住一次机会打了一个“探头球”,已知来球速度为10 m/s,击回的球速度大小为20 m/s,击球时间为0.05s,假设速度方向均为水平方向,求:击球过程中排球的加速度。
解:设排球的初速度方向为正,则由加速度定义得a=m/s2=-600 m/s2,即加速度的大小为600 m/s2,方向与初速度方向相反
阅读短文,完成下面的日历表。 | ||||||||||||||||
Thank you for your invitation to visit next week. I'm sorry, but I can't come. I have a really busy week. This evening I'm going to my cousin's birthday party. And tomorrow, I have to go to the dentist. The day after tomorrow I'm playing tennis with the school team. And I have to study for my science test on Thursday. After Thursday, I'm going sightseeing with my family for one and a half days. We're going to have a big dinner in the evening when we are back home. | ||||||||||||||||
|