POS analyze mechanical devices to determine speed ratios and force ratios identify linkages and power transmissions in a mechanical device, and describe their general function (e.g., identify the purpose and general function of belt drives and gear systems within a mechanical device) build or modify a model mechanical system to provide for different turning ratios between a driving and driven shaft, or to achieve a given force ratio

POS compare theoretical and actual values of force ratios, and propose explanations for discrepancies (e.g.,identify frictional forces, and estimate their effect on efficiency) identify work input and work output in joules for a simple machine or mechanical system (e.g., use a device to lift a measured mass an identified distance, then calculate the work output)

Lesson 2: Gears + Work

Types of Gears Parallel Multiplying Reducing Transmissions Linkages (see gears notes-blue book)

The Egg Beater Is this a multiplying, reducing, or parallel set of gears? Are there any other simple machines visible in this device?

The Egg Beater Is this a multiplying, reducing, or parallel set of gears? Multiplying. The driving gear is larger than the driven gear, creating a speed advantage. Are there any other simple machines visible in this device? Wheel and axle

Work W = F x d Work is the force applied over a given distance Where W is the energy, measured in Joules (J) F is the force, measured in Newtons (N) D is the distance, measured in meters (m) Note: a J = Nm

Pyramid of ultimate knowledge Aka -easy way to re-arrange formulas W = F x d F = W / d d = F / w

Steps for solving problems 1) List your variables (what is the question?) 2) Write the formula (re-arrange if necessary) 3) Plug in the numbers into the formula (with units!!!) 4) give your answer in a box/highlighted 5) write a detailed sentence explaining your answer

Work ex 1) The cart needed to be pushed down the 30 m hallway with a force of 20 N. How much work was done by the student?

Work ex 1) solution W=? J F= 20 N d= 30 m W=F x d W = 20N x 30m W= 600 Nm (600 J) The work done by the student pushing the cart down the hallway was 600 J.

Work ex 2) In wrestling, you pushed against Mr. Villeneuve with a force of 200 N, but he didn’t budge. How much work was done?

Work ex 2) solution W=? J F = 200 N d = 0 m W =F x d W = 200N x 0m You did not do any work (0 J)as there was no change in distance.

Work ex 3) What was the force of a tree that fell and dented a car by 5 cm? The amount of energy absorbed was 500 J.

Work ex 3) solution W=500 J F= ? N d= 5 cm = 0.05 m W=F x d F =W/d F = 500 N / 0.05 m W= 10,000 N The force of the tree falling on the car was 10,000 N.

Assignments Lab pg 274- Analyzing gears on a bike “What is work” Work Questions pg 292#1-9 Section 2.0 Journals (read + take notes) Vocabulary

Lesson 3:Mechanical advantage, Speed ratios, Efficiency Mr. Schumack notes

Assignments Mechanical Advantage Problems Efficiency Calculations Worksheet Simple Machines Cryptic Pg 286 #2-5 Topic 2.1 Worksheet Calculation Practice (with boxes): for marks

Lesson 4: Pressure (see notes Mr. Schumack) Pressure is the force applied over a given surface area (review from chem unit) P = F / A Where P is the pressure, measured in Pascals (Pa) F is the force, measured in Newtons (N) A is the surface area, measured in meters (m2) Note: a Pa = N/m2

Assignments Pg 300 #1-4, 303 #3,5

Lesson 5 Evaluating Mechanical Devices As a class, read section 3.0 pgs 304-319, discuss the answers to questions along the way Unit Review Q’s pg 325-327 Unit Review booklet

Pulleys Pulley Power Worksheet