velocity of radar waves

例句：

1. 1.The car accelerated to 60 miles per hour.
   汽车以每小时60英里的速度加速。
2. 2. The ship's speed was measured at 25 knots.
   这艘船的速度被测量为每小时25节。
3. 3.The train's velocity is much higher than the plane's.
   火车的速度远高于飞机的速度。