【单选题】关于功率,下列说法中正确的是
A.
功率是描述做功快慢的物理量,在国际单位制中,其单位是焦耳 (J)
B.
功率是描述做功快慢的物理量,在国际单位制中,其单位是瓦特 (W)
C.
功率是描述做功多少的物理量,在国际单位制中,其单位是焦耳 (J)
D.
功率是描述做功多少的物理量,在国际单位制中,其单位是瓦特 (W)
【单选题】关于功率 , 下列说法中正确的是
C.
由 P = W / t 可知机器做功越多 , 其功率越大
【判断题】植物检疫又称为法规防治,是利用立法和行政措施防止或延缓有害生物的人为传播。
【简答题】Jack is six. He is old enough to go to school. On the first day, his teacher teaches him three words,“l, you, he”.Then the teacher says, “I am your teacher. You are my student. He is your classmate.” ...
【简答题】阅读下面短文,掌握其大意,从A、B、C、D四个选项中选出最佳选项。 Dear Dad, I’m writing to you because it’s not easy to talk about it. I still 1 clearly how my uncle died two years ago. In fact, I seriously want to ask you to stop s...
【单选题】关于功率,下列说法中正确的是
B.
根据P=Fv可知,汽车的牵引力一定与速率成反比
C.
由P=W/t可知,只要知道t时间内力所做的功,就可以求得这段时间内任一时刻的功率
D.
由P=Fv可知,当发动机功率一定时,交通工具的牵引力与运动速率成反比
【简答题】信息归纳。 Dear Dad and Mum, How are you? I hope you are well. I have been in Beijing for about two months and I enjoy living here very much. The weather here is pretty cold and people are friendly. I work...