英语拓展模块Grammar课前预习课件ppt

这是一份英语拓展模块Grammar课前预习课件ppt，共14页。PPT课件主要包含了功和功率，WFS，Example，Work done ，4000J， joule，Power ，watt，Power，Sum up等内容，欢迎下载使用。
Wrk and Pwer
* 功表示力和受力物体在力的作用方向上发生的位移的乘积。
*功率表示力做功的快慢程度。
Fast reading
Read the text quickly and answer the fllwing is the definitin f “wrk”?2.Hw d yu calculate the amunt f wrk dne?3.What is the definitin f 1 jule?4.What is the definitin f “pwer”?5.What is the definitin f 1watt?
Wrk is dne when a frce causes an bject t mve r prevents it frm mving.
the definitin f “wrk”:
Equatin : W=F*S
Wrk dne= frce X distance mved in the directin f the frce
Wrk dne equals frce times distance mved in the directin f the frce.
An athlete applies a frce f 2000 newtns t mve up the weights t the height f 2 meters. Hw much wrk has the athlete dne?
= 2000N X 2m
If a frce f 1 N causes an bject t mve 1 meter, then 1J f wrk has been dne.
The definitin f “pwer”
Pwer is a measure f hw rapidly wrk is being dne.
If a persn r a machine is ding 1J f wrk each secnd ,the pwer rating is 1 W.
G n lking at the athlete, if the wrk takes the athlete 0.5secnd t lift the weights abve his head, what is the pwer f the athlete?
=8000Wr 8Kw
Wrk ; wrk dne ;1 Jule; pwer; 1Watt.Wrk dne=2000N X 2m=4000JPwer=4000J ÷0.5s=8000w r 8kw
The lawnmwer mve needs 80 newtns, its engine can apply 50 newtns. A lady pushed the lawnmwer alng a straights line fr 40 meters. Hw much wrk has the lady dne?