So this city is not a city in New England, it's a city in the Midwest, where everything's flat and the roads just go completely straight.

所以这不是在新英格兰的城市,它是美国中西部的城市,那里都是平坦而笔直的路

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Then it lands on your foot, because assuming the cannon is at zero height, the cannonball certainly comes out towards the enemy, but has no time of flight.

然后它就会落在你的脚边,因为假设大炮的高度为 0,炮弹笔直地出膛打向敌人,却没有时间飞行

耶鲁公开课 - 基础物理课程节选