Simple machines TECHNOLOGY Simple Machines Give me a

Simple machines TECHNOLOGY Simple Machines “Give me a place to stand I will move the Earth” Archimedes of Syracuse (c. 287 BC – c. 212 BC) Carles Egusquiza Bueno 1 IES Rocagrossa – Lloret de Mar

Simple machines TECHNOLOGY Unit 1: Force, work and machines Lever Carles Egusquiza Bueno Inclined plane 2 IES Rocagrossa – Lloret de Mar

Simple machines TECHNOLOGY Screw Wheel Carles Egusquiza Bueno 3 IES Rocagrossa – Lloret de Mar

Simple machines TECHNOLOGY Pulley Wedge Carles Egusquiza Bueno 4 IES Rocagrossa – Lloret de Mar

Simple machines TECHNOLOGY Lesson 1: FORCE push pull force Carles Egusquiza Bueno pull force push force 5 IES Rocagrossa – Lloret de Mar

Simple machines TECHNOLOGY accelerate decelerate divert deform Carles Egusquiza Bueno 6 IES Rocagrossa – Lloret de Mar

Simple machines Carles Egusquiza Bueno TECHNOLOGY 7 IES Rocagrossa – Lloret de Mar

Simple machines TECHNOLOGY Lesson 2: WORK AND ENERGY Student B did double the work of student A Student C did double the work of student A Student D did four times the work of student A Student B did half the work of student D Student C did the same work as student B Carles Egusquiza Bueno 8 IES Rocagrossa – Lloret de Mar

Simple machines TECHNOLOGY The bigger the force, the bigger the work The longer the distance, the bigger the work So, mathematically… Work = Force x distance W=Fxd Carles Egusquiza Bueno 9 IES Rocagrossa – Lloret de Mar

Simple machines Carles Egusquiza Bueno TECHNOLOGY petrol transport people food run electricity phone wind generate electricity 10 IES Rocagrossa – Lloret de Mar

Simple machines TECHNOLOGY Energy… is the ability to do work. ENERGY Carles Egusquiza Bueno MACHINE 11 WORK IES Rocagrossa – Lloret de Mar

Simple machines Carles Egusquiza Bueno TECHNOLOGY 12 IES Rocagrossa – Lloret de Mar

Simple machines TECHNOLOGY 10 m pushes work 200 N makes move force process pulls work 400 N force distance Carles Egusquiza Bueno rope 15 m height lift 4500 J force applied motorbike lift 20000 J work process motorbike 13 IES Rocagrossa – Lloret de Mar

Simple machines TECHNOLOGY 1. A road vehicle with two wheels is a… motorbike 2. What’s the name of the distance between the ground and something above it? Height lift something, you elevate it. 3. If you ……. . 4. It is a thick cord or wire. Rope process is a series of actions which are executed in order to achieve a result. 5. A ……. force is any cause that can change the movement or the shape of an object. 6. A …………… 7. When you move something making a force, you are doing… work 8. To use force in order to move something towards you. To pull 9. To use force to make something move away from you. To push Carles Egusquiza Bueno 14 IES Rocagrossa – Lloret de Mar

Simple machines TECHNOLOGY W=Fxd Remember… W F d Carles Egusquiza Bueno Work Unit to measure work: JOULE (J) Force Unit to measure force: NEWTON (N) Distance Unit to measure distance: METRE (m) 15 IES Rocagrossa – Lloret de Mar

Simple machines TECHNOLOGY F = 200 N d = 10 m Carles Egusquiza Bueno 16 IES Rocagrossa – Lloret de Mar

Simple machines Carles Egusquiza Bueno TECHNOLOGY 17 IES Rocagrossa – Lloret de Mar

Simple machines TECHNOLOGY Lesson 3: MACHINES Carles Egusquiza Bueno 18 IES Rocagrossa – Lloret de Mar

Simple machines Carles Egusquiza Bueno TECHNOLOGY 19 IES Rocagrossa – Lloret de Mar

Simple machines TECHNOLOGY What’s a machine? A m a c h i n e i h a t u e e n p e r f o r m t Carles Egusquiza Bueno o m e 20 a n y d e e r g y t o v i a c t i v i t c e y IES Rocagrossa – Lloret de Mar

Simple machines TECHNOLOGY Sentence 1 Usually cars have four wheels but motorbikes and bicycles have just two. Sentence 2 To get high speed in ski jumping, skiers slide down a ramp or inclined plane. Carles Egusquiza Bueno 21 IES Rocagrossa – Lloret de Mar

Simple machines TECHNOLOGY Sentence 3 Screws can be used to join pieces but also to make moving devices like a car’s jack. Sentence 4 Taking water from a well is much easier if you have a rope and a pulley. Carles Egusquiza Bueno 22 IES Rocagrossa – Lloret de Mar

Simple machines TECHNOLOGY Sentence 5 You can cut logs with a saw or you can split them with a wedge and a sledgehammer. Sentence 6 A wooden pallet is easier to break if you have a crowbar to use as a lever. Carles Egusquiza Bueno 23 IES Rocagrossa – Lloret de Mar

Simple machines TECHNOLOGY 1. What is a simple machine? A simple machine is a device that changes the direction or the magnitude of a force. 2. Why are simple machines useful? Simple machines are useful because they make work easier. 3. How does a simple machine work? A simple machine works by using a single applied force to do work against a load. 4. How many moving parts has a simple machine got? A simple machine has got few or no moving parts. 5. Why is learning the basics of simple machines important? Learning the basics of simple machines is fundamental to understanding more intricate mechanisms. 6. What’s the relationship between simple machines and more complicated machines? Simple machines can be thought of as building blocks for more complicated machines. Carles Egusquiza Bueno 24 IES Rocagrossa – Lloret de Mar

Simple machines TECHNOLOGY 7. Which are the two basic simple machines? The two basic simple machines are the inclined plane and the lever. 8. What devices are variants on the inclined plane? The screw and the wedge are variants on the inclined plane. 9. What devices are variants on the lever? The wheel and axle and the pulley are variants on the lever. Simple machines Inclined plane Screw Carles Egusquiza Bueno Lever Wheel and axle Wedge 25 Pulley IES Rocagrossa – Lloret de Mar

Simple machines TECHNOLOGY Lesson 4: MECHANICAL ADVANTAGE Carles Egusquiza Bueno 26 IES Rocagrossa – Lloret de Mar

Simple machines Carles Egusquiza Bueno TECHNOLOGY 27 IES Rocagrossa – Lloret de Mar

Simple machines TECHNOLOGY a) Conservation of energy principle: Energy can neither be created nor destroyed; it can only be transformed from one state to another. b) Friction: Force that makes the relative motion between two objects more difficult. c) Frictionless system: Ideal system with no friction forces within it. d) Ideal machine: Theoretical machine in which there is no loss of energy (e. g. , because of the friction). e) Actual machine: Machine in which there is loss of energy (i. e. , real machine) f) Efficiency: Is the ratio of energy used by a machine to the useful work the machine has done. Carles Egusquiza Bueno 28 IES Rocagrossa – Lloret de Mar

Simple machines TECHNOLOGY mb = 280 kg F FRA GIL E L mm = 70 kg Carles Egusquiza Bueno 29 IES Rocagrossa – Lloret de Mar

Simple machines TECHNOLOGY mb = 280 kg F FRA GIL E mm = 70 kg L mm L F Mass of the man. mb Unit to measure mass: KILOGRAM (kg) Mass of the object we want to move. Unit to measure mass: KILOGRAM (kg) Load we want to move. It’s the weight of the object. It can also be called resistance or output force. Unit to measure force: NEWTON (N) Force we have to apply to move the object. It can also be called effort or input force. Unit to measure force: NEWTON (N) Carles Egusquiza Bueno 30 IES Rocagrossa – Lloret de Mar

Simple machines TECHNOLOGY mb = 280 kg F FRA GIL E mm = 70 kg L The load L is the weight of the box, so… If the man hang from the bar to move the box, his weight will be the force F: Carles Egusquiza Bueno 31 IES Rocagrossa – Lloret de Mar

Simple machines TECHNOLOGY mb = 280 kg mm = 70 kg MA = 4 FRAGILE L = 1692 N F = 686, 7 N The man can lift 1692 N (280 kg) applying a force of 686, 7 N (70 kg). The force done is a quarter of the force we would need to lift the box without the bar. The machine (in this case, a lever) multiplied the force of the man by 4. This number is called mechanical advantage (MA). Carles Egusquiza Bueno 32 IES Rocagrossa – Lloret de Mar

Simple machines TECHNOLOGY Mechanical advantage (MA) is… … the factor by which a machine multiplies the force applied to it. … the force amplifying effectiveness of a simple machine. … the ratio of load to effort. … the ratio of the force exerted by a machine (the output) to the force exerted to the machine (the input). In the example: =4 Carles Egusquiza Bueno 33 IES Rocagrossa – Lloret de Mar

Simple machines TECHNOLOGY mb = 280 kg mm = 70 kg 1. Do simple machines multiply energy? MA = 4 No, simple machines do not multiplying energy but force. F = 686, 7 N FRAGILE L = 1692 N 2. What’s the relationship between the input energy and the output work of an actual machine? Why? The input energy of an actual machine is always bigger than its output work. The reason is that in actual machines there is always a loss of energy due to friction. The efficiency is not 100%. Winput > Woutput 3. What’s the relationship between the input energy and the output work of an ideal machine? Why? The input energy of an ideal machine is equal to its output work. The reason is that in ideal machines there is no loss of energy due to friction. The efficiency is 100%. Winput = Woutput Carles Egusquiza Bueno 34 IES Rocagrossa – Lloret de Mar

Simple machines TECHNOLOGY 4. What principle related to energy do simple machines violate? Why? None because no energy is created by simple machines. They just multiply force. The conservation of energy principle cannot be violated. Winput = Woutput 5. What’s the cost of making less force with a simple machine to get the same energy? To get the same energy with less force you have to apply the force over a longer distance. dm db Carles Egusquiza Bueno 35 In the example, to move the box a short distance (db), the man had to move the other part of the lever a long distance (dm). IES Rocagrossa – Lloret de Mar

Simple machines TECHNOLOGY 5. How can we get the mechanical advantage formula? By applying the conservation of energy principle. The ratio of distances is equal to the ratio of forces. We call that ratio mechanical advantage. Carles Egusquiza Bueno 36 IES Rocagrossa – Lloret de Mar

Simple machines Carles Egusquiza Bueno TECHNOLOGY 37 IES Rocagrossa – Lloret de Mar

Simple machines Carles Egusquiza Bueno TECHNOLOGY 38 IES Rocagrossa – Lloret de Mar

Simple machines Carles Egusquiza Bueno TECHNOLOGY 39 IES Rocagrossa – Lloret de Mar