So you cannot use the formula once it hits the ground because once it hits the ground, the fundamental premise that a was a constant of -9.8 or -10 is wrong.

当物体落地以后,该公式就不适用了,因为当物体落地后,公式的基本前提——,加速度为常数-9.8或-10——就不成立了

耶鲁公开课 - 基础物理课程节选

But even if you do survive-- let's the ground floor-- even if you do survive, you would lead a life of constant frustration-- refusing to accept something that is there whether you like it or not.

即使你幸存下来-,比如你在一楼-,就算你真得幸存下来，你的生活将是处处受挫-,拒绝接受现实事物,不论你喜欢与否。

哈佛公开课 - 幸福课课程节选

If close relationships trigger attachments that ground people, then a phone is a constant source of reinforcement as it consistently dispenses rewards.

FORBES: Love, Sex and Your Smartphone

Through chat windows, they exchange data, update intelligence reports and talk in real time with commanders on the ground, including troops whose lives may depend on the constant and rapid flow of information they get from Langley.

NPR: AP IMPACT: Combat Stress Felt Far From Front Lines

Because I've been working down there for nearly a year as the U.N. special envoy, I've been in constant touch with our people through the U.N. on the ground, and you know we lost a lot of our people there -- the largest loss of life in the history of the United Nations on a single day.

WHITEHOUSE: Presidents Obama, Bush, & Clinton: Help for Haiti