蜗牛沿直线爬行速度缓慢，小明突然想：蜗牛是匀速运动的吗？他用停表和刻度尺测出了蜗牛运动的距离和时间如下表．
| 距离/mm | 0 | 2.4 | 3.6 | 4.8 | 6.0 | 7.2 |
| 时间/s | 0 | 1 | 1.5 | 2 | 2.5 | 3 |
（2）在整个测量过程中，蜗牛的平均速度为______mm/s．
（1）第一个2.4mm所用的时间是1s，
第二个2.4mm所用的时间是1s，
第三个2.4mm所用的时间是1s，
由此可知，蜗牛做的是匀速运动，因为蜗牛在相等的距离内所用的时间相等．
（2）蜗牛在整个测量过程中的平均速度：V=
=S t
=2.4mm/s．7.2mm 3s
故答案为：（1）是；（2）2.4．
| 阅读短文，判断句子对(√)错(×)。 | |
two beds (床). On Lucy's bed you can see some books. On Joan's bed you can see a kite and a doll. There are two chairs and a desk (桌子) in the room. Their pens and clock (钟表) are on the desk. Look! It's 7: 30. It's time to go to school (到去上学的时间了). ( ) 1. Lucy and Joan have two beds. ( ) 2. There is a kite and a doll on Joan's bed. ( ) 3. You can see two desks in the room. ( ) 4. Their pens and clock are on the desk. |
