October 7, 2009 IOT POLY ENGINEERING I1-25 DRILL: A.LIST 5 BASE UNITS AND DESCRIBE WHAT THEY ARE USED TO MEASURE. B.LIST 5 DERIVED UNITS AND DESCRIBE WHAT THEY ARE USED TO MEASURE.

IOT POLY ENGINEERING I1-25 Answers to today’s Drill BASE UNITS: SECOND – TIME KILOGRAM – MASS METER – LENGTH CANDELA – LUMINOUS INTENSITY KELVIN – THERMODYNAMIC TEMPERATURE MOLE – AMOUNT OF SUBSTANCE AMPERE – ELECTRIC CURRENT DERIVED UNITS: METERS/SECOND – SPEED CUBIC METERS – VOLUME JOULE – ENERGY NEWTON – FORCE KILOGRAM METER/SEC – MOMENTUM … and many more

IOT POLY ENGINEERING I1-25 SUMMARY OF THE 7 FUNDAMENTAL SI UNITS: 1.LENGTH - meter 2.MASS - kilogram 3.TIME - second 4.ELECTRIC CURRENT - ampere 5.THERMODYNAMIC TEMPERATURE - Kelvin 6.AMOUNT OF MATTER - mole 7.LUMINOUS INTENSITY - candela

IOT POLY ENGINEERING I1-25 COMPLETE THE CHART AND GRAPH ON TODAY’S PRINTED HANDOUT SHEET.

IOT POLY ENGINEERING I1-25 The engineer of an express train traveling at 30 m/s notices a freight train 84 meters up ahead traveling in the same direction at only 10 m/s. The engineer immediately puts on the brakes and the train decelerates at 2 m/s/s. Will the trains collide? Explain. If there is a collision, how many seconds after the engineer puts on the brakes will the trains collide? If there is not a collision, how far apart will the trains be when the express train finally stops?

IOT POLY ENGINEERING I1-25 This problem is very difficult, but can be solved with algebra and a graph. We need to determine if both trains are ever in the same place at the same time. We will calculate the distance of each train based upon the location of the express train when the brakes were applied. The distance traveled by the freight train is given by: D = t The distance traveled by the express train is given by: D = 30 t – t 2

IOT POLY ENGINEERING I1-25 The distance traveled by the freight train is given by: D = t The distance traveled by the express train is given by: D = 30 t – t 2 The express train loses 2 m/s of speed every second, so we could assume that it will lose all 30 m/s of its original speed within 15 seconds. Now, let’s calculate where each train is located at t=15 seconds using the equations above. D = (15) = = 234 meters D = 30 (15) – (15 2 ) = 450 – 225 = 225 meters At the end of the 15 seconds, we conclude that there is not a collision. Now, let’s solve the same problem using a graph.

IOT POLY ENGINEERING I1-25 COMPLETE THE CHART AND GRAPH ON TODAY’S PRINTED HANDOUT SHEET. For every second of time, determine the location of each train from the original location of the express train. The freight train starts at 84 meters, while the express train begins at 0 meters. Based on the graph of each train’s location, what is your conclusion?

IOT POLY ENGINEERING I1-25 October 14, 2009 HOMEWORK: Study for the upcoming test on Unit 1.