Contact us
Choose a category below so we can get back to you as quickly as possible.
速率沒有方向只有大小,它是運動物體經過的路程△S和通過這一路程所用時間△t的比值 速度有大小也有方向,它是運動物體經過的位移△S和通過這一路程所用時間△t的比值
We and our partners use cookies and other technologies to analyze traffic and optimize your experience. View more info and control your cookies settings at any time in our Cookies Policy.