Advanced Design Applications Power and Energy © 2014 International Technology and Engineering Educators Association STEM  Center for Teaching and Learning™ Advanced Design Applications Teacher Resource Learning Cycle 3

The BIG Idea  Big Idea: Energy and Power are technologies that are necessary to use in the designed world. Reviewing simple machines and learning how they can be used to manipulate mechanical advantage will allow users to take advantage of energy and power that is generated. © 2014 International Technology and Engineering Educators Association STEM  Center for Teaching and Learning™ Advanced Design Applications

Simple Machines Review © 2014 International Technology and Engineering Educators Association STEM  Center for Teaching and Learning™ Advanced Design Applications

Inclined Plane A sloping surface or ramp... Used to alter the effort and distance involved in doing work. Examples: lifting loads, staircases, bottom of a bathtub Compromise or trade-off: object must move a longer distance than if it was lifted straight up, but less force is required © 2014 International Technology and Engineering Educators Association STEM  Center for Teaching and Learning™ Advanced Design Applications

Inclined Plane Calculation Example A man pushes a cylinder up a smooth inclined plane. The cylinder weighs 70 pounds. The ratio of the triangle’s height to its hypotenuse determines how much effort the man must exert to move the cylinder up the plane at a uniform speed. © 2014 International Technology and Engineering Educators Association STEM  Center for Teaching and Learning™ Advanced Design Applications

Inclined Plane Situation 1  Distance rolled = 2 feet. Desired lift = 1 foot.  Effort = weight x (triangle’s height/triangle’s hypotenuse)  Effort = 60 pounds x (1 foot /2 foot) = 30 pounds Situation 2  Distance rolled = 3 feet. Desired lift = 1 foot.  Effort = weight x (triangle’s height/triangle’s hypotenuse)  Effort = 60 pounds x (1 foot /3 foot) = 20 pounds © 2014 International Technology and Engineering Educators Association STEM  Center for Teaching and Learning™ Advanced Design Applications

Inclined Plane Situation 3  Distance rolled = 4 feet. Desired lift = 1 foot.  Effort = weight x (triangle’s height/triangle’s hypotenuse)  Effort = 60 pounds x (1 foot /4 foot) = 15 pounds © 2014 International Technology and Engineering Educators Association STEM  Center for Teaching and Learning™ Advanced Design Applications

Lever A piece of material that pivots on a fulcrum... The fulcrum is moved based on the weight of the object to be lifted and the desired effort to be exerted. Examples: hammer, bottle opener, breaker bar Similar to the inclined plane, the weight and distance have an inverse relationship. To increase the weight being lifted → relocate the fulcrum or change the force doing the lifting. © 2014 International Technology and Engineering Educators Association STEM  Center for Teaching and Learning™ Advanced Design Applications

Lever Calculation example: Two children are on a see-saw. They both want to go up together on the same side, and they want to go very high. The children weigh 55 and 60 pounds. The see-saw board has a length of 12 feet. If the fulcrum is moved from the center by 2 feet to raise the children higher, what would be the minimum weight for a person to raise them on the other side? © 2014 International Technology and Engineering Educators Association STEM  Center for Teaching and Learning™ Advanced Design Applications

Lever Calculation example:  Weight of side 1 (fulcrum distance for side 1) = weight of side 2 (fulcrum distance for side 2)  Weight 1 (6 feet – 2 feet) = ( pounds) (6 feet + 2 feet)  Weight 1 (4 feet) = (115 pounds) (8 feet)  Solve for the unknown quantity!  Weight 1 = [(115 pounds) (8 feet)]/(4 feet)  Weight 1 = 230 pounds © 2014 International Technology and Engineering Educators Association STEM  Center for Teaching and Learning™ Advanced Design Applications

Pulley A wheel that changes the direction of the force that is applied... Additional pulley wheels reduce the effort involved with lifting. Examples: flag, mini-blinds A single pulley reduces “work” because gravity is working with you when you are pulling down on the rope. © 2014 International Technology and Engineering Educators Association STEM  Center for Teaching and Learning™ Advanced Design Applications

Screw An inclined plane wrapped around a cylinder... Use circular motion to raise or lower an object (vertically). Examples: bolt, spiral staircase The speed of the vertical motion is influenced by the distance between the threads (the pitch). © 2014 International Technology and Engineering Educators Association STEM  Center for Teaching and Learning™ Advanced Design Applications

Wedge A modified form of the inclined plane... By bisecting the angle made by the point of the wedge, you can see that this simple machine is two inclined planes placed face to face. Examples: axe, scissors, knife This machine can sustain relative sliding or rolling motion. It can build up enormous force in a direction perpendicular to movement. © 2014 International Technology and Engineering Educators Association STEM  Center for Teaching and Learning™ Advanced Design Applications

Wheel and Axle Two cylinders joined together... Fastened together so they rotate as a unit. Examples: toy car, door knob When the axle is turned, the wheel moves a greater distance, but less force is needed to move it. Conversely, the axle moves a shorter distance, but more force is required to move it. © 2014 International Technology and Engineering Educators Association STEM  Center for Teaching and Learning™ Advanced Design Applications

Gears A wheel with teeth... Transfers motion directly (mating with other gears) or indirectly (mating with a chain or belt). Examples: clock, drills Speed and torque can be manipulated through tooth ratios. Speed is increased when number of teeth is decreased. Torque is increased by decreasing speed. © 2014 International Technology and Engineering Educators Association STEM  Center for Teaching and Learning™ Advanced Design Applications

Gears Gear Calculation 1 A spinning gear that has 33 teeth in a transmission is spinning 1200 RPM. It is connected to another gear that is spinning 3600 RPM. How many teeth does the other gear have? Setting up a ratio: 33 = 3600 X = 1200 © 2014 International Technology and Engineering Educators Association STEM  Center for Teaching and Learning™ Advanced Design Applications

Gears Gear Calculation 1 Cross multiply and solve for X: 33 (1200) = X (3600) = X (3600) X = 39600/3600 = 11 Units are eliminated from this calculation for demonstration purposes. © 2014 International Technology and Engineering Educators Association STEM  Center for Teaching and Learning™ Advanced Design Applications

Gears Gear Calculation 2 A gear is spinning at 10,000 RPM and has a torque of 2 in-lb. You change the speed of the mating gear by changing the teeth. It is spinning at 1500 RPM. What is its torque value? Setting up a ratio: Y = = 1500 © 2014 International Technology and Engineering Educators Association STEM  Center for Teaching and Learning™ Advanced Design Applications

Gears Gear Calculation 2 Cross multiply and solve for Y: Y (1500) = 2 (10000) Y (1500) = X = 20000/1500 = 13.3 Units are eliminated from this calculation for demonstration purposes. © 2014 International Technology and Engineering Educators Association STEM  Center for Teaching and Learning™ Advanced Design Applications