"The Speed ​​of Work" Machinery and Human PPT Courseware

Description

"The Speed ​​of Work" Machinery and Human PPT Courseware

think about it

(1) What are the two necessary factors for doing work? Give two examples of work being done and work not being done.

(2) The formula and unit of work.

How to compare the speed of exercise?

Method 1: The time taken is the same, the longer the distance the faster

Method 2: Traveling the same distance in less time is faster

Method 3: Look at the distance traveled per unit time

How to compare the speed of work?

Method 1: It takes the same time, and the one who does more work will do it faster.

Method 2: To do the same work, the one that takes less time will do it faster.

Method 3: Look at the work done per unit time

power

1. Definition: The ratio of the work done in a period of time to the time used to do the work is called power.

2. Expression: Power=work/time, that is, P=W/T

3.Unit

SI unit: Watt, symbol W

1W＝1J/s

Commonly used units: kilowatt (k W)

1 kilowatt = 1000 watts

Note: The symbol of work is W, and the symbol of power unit is W.

practice

1. The ratio of the work done in a period of time to the time spent doing the work is called power.

Its formula is ________, and the unit of power is ____.

2. What is the physical meaning of power 70W? Which one has greater power, 70W or 450W? Which one does the work faster? Which one does more work?

A power of 70W means that the machine has done 70J of work in 1 second.

450W has greater power than 70W and works faster.

450W＝450J/s, 70W＝70J/s

3. When using machinery to perform work, which of the following statements is correct: ( )

(A) A machine with high power must do more work than a machine with low power;

(B) A machine with high power must take less time to do work than a machine with low power;

(C) A machine with low power must do work slower than a machine with high power;

(D) None of the above statements are correct.

Keywords: Teaching courseware of machines and people, teaching courseware of the speed of doing work, download of the complete eighth grade physics PPT courseware of Shanghai Science Edition, download of the eighth grade physics slide courseware, download of the PPT courseware of machines and people, download of PPT courseware of the speed of doing work,. PPT format;

For more information about the PPT courseware "How quickly machines and people do work", please click the "How quickly machines and people do work" ppt tag.

"How to compare the speed of work" Mechanical work and mechanical energy PPT courseware 2:

"How to Compare the Speed ​​of Work" Mechanical Work and Mechanical Energy PPT Courseware 2 1. How to Compare the Speed ​​of Work Do cars and trains do work at the same speed? Which one does the work faster, man or crane? How did you compare? Doing the same amount of work takes different time...

"How to compare the speed of work" PPT courseware on mechanical work and mechanical energy:

"How to Compare the Speed ​​of Work" PPT Courseware on Mechanical Work and Mechanical Energy Learning Objectives 1. Understand the concept of power. 2. Know the calculation formula of power and the meaning of power units, and be able to calculate simple problems related to power. 3． Through the process of establishing power concepts, deepen...

"How fast electric current does work" Current work and electric power PPT courseware 3:

"How Fast or Slow Electric Current Does Work" Current Work and Electric Power PPT Courseware 3 The aluminum plate on the electric energy meter in our home sometimes moves slowly, sometimes in a hurry. why? What does the rotation speed of the aluminum disk have to do with it? The aluminum disk rotates at different speeds, indicating how quickly the electrical appliance consumes electricity..

File Info

Update Time: 2024-11-16

This template belongs to Physics courseware Shanghai Science Edition 8th Grade Physics industry PPT template

Preview