Unit 2: Energy Flow in Global Systems

Chapters:

• Chapter 4: Thermal Energy and Work• Chapter 5: Energy and Motion• Chapter 6: Efficiency

Chapter 4: Thermal Energy and Work

Assignment #2:

• Read Pages 142 – 149Create a chart on the following inventors:• The First Steam Engine(Thomas Savery)• James Watt’s improvement of the Steam

engine• Steam Engines today (choose any engineer)

Include the following for each Inventor:

– Background: when the inventor was born, where he lived etc – Rationale: outline the rationale or reasoning for developing

his steam engine – Design: describe the design of his engine and how it works– Diagram: locate and include a diagram or a picture of the

inventors steam engine – Benefits/Drawbacks: list the benefits and/or drawbacks to

the design– Common Links: discuss how the development of the steam

engine progressed from all three inventors and how they are

Work and Force:

What is a Force?A push or a pull in any direction Measured in Newton’sVariable: FUnit: N

Work:

What is Work?Work is a form of EnergyPush or a Pull in the direction intended over a distanceMeasured in JoulesVariable: WUnit: J (N x m)

Is Work Being Done?

Formula:

Work = Force x distanceW = FdW = Joules (J)F = Newtons (N)d = distance (m)Re-Arrangement:F = W d = W d F

Ex 1: You exert a force of 25 N on your textbook while lifting it a height of 1.4 m to put it on a shelf. How

much work did you do on your textbook?

Step 1: List Variables Step 2: Choose FormulaF = 25 N W = Fdd = 1.4mW = ?

Step 3: Plug-in(with units) Step 4: SolveW = (25N)(1.4m) W = 35J

Rounding and Significant Figures:

Rule: Your answer must have the same number as digits as the variable(in your question) with the LEAST amount of digits

Refer to text page 492