| 1. | The velocity of light is about 300,000 kilometres per second .
光速约为每秒30万公里。 |
| 2. | Its decay probability per second is the inverse of this time .
每秒的衰变几率是这个时间的倒数。 |
| 3. | The whole drum rotates at a steady speed of about sixty revolutions per second .
整个磁鼓大约以每秒60转的恒定转速旋转。 |
| 4. | The signals carried in copper wires consist of about one million waves per second .
在铜线中传送的信号是由大约每秒100万次波的电磁波所组成。 |
| 5. | At low frequencies , such as 10 per sec. , pulsation is sensed rather than vibration .
在低频率（譬如每秒十次）时，所感觉到的是脉冲而非振动。 |
| 6. | The fireball ascended with great rapidity, the initial rate of rise being about a mile per second .
火球以很高的速度上升，上升的最初速度约为每秒1哩。 |
| 7. | The filaments are expanding into space at a speed of roughly 5, 000 kilometers per second .
这些纤维状星云物质以每秒大约5000公里的速度向宇宙空间扩展。 |
| 8. | A light-year is the distance light travels in one year at a speed of 299, 792 kilometers per second .
一光年是光以每秒299792公里的速度在一年中所走过的距离。 |
| 9. | Now a joke on a wireless programme leaps across the world at a speed of 186, 000 miles a second .
而现在，即使是无线电节目里的一个笑话，也以每秒186，000英里的速度传遍世界。 |
| 10. | In cumulus convection ascent rates of several metres a second give a cooling rate of a few degrees per minute .
在积云中，每秒几米的对流上升速度造成的冷却速率为每分钟几度。 |
