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Simple machines TECHNOLOGY Carles Egusquiza Bueno IES Rocagrossa – Lloret de Mar 1 “Give me a place to stand and I will move the Earth” Simple Machines.

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Presentation on theme: "Simple machines TECHNOLOGY Carles Egusquiza Bueno IES Rocagrossa – Lloret de Mar 1 “Give me a place to stand and I will move the Earth” Simple Machines."— Presentation transcript:

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

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

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

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

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

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

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

9 Simple machines TECHNOLOGY Carles Egusquiza Bueno IES Rocagrossa – Lloret de Mar 8 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 Lesson 2: WORK AND ENERGY

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

11 Simple machines TECHNOLOGY Carles Egusquiza Bueno IES Rocagrossa – Lloret de Mar 10 petrol transport people foodrun electricityphone wind generate electricity

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

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

14 Simple machines TECHNOLOGY Carles Egusquiza Bueno IES Rocagrossa – Lloret de Mar 13 pushes 10 m move makes 200 Nforce workprocess pulls rope lift height 15 m work 4500 J forcelift 400 Nforce appliedmotorbike J work process motorbikedistance

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

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

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

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

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

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

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

22 Simple machines TECHNOLOGY Carles Egusquiza Bueno IES Rocagrossa – Lloret de Mar 21 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.

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

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

25 Simple machines TECHNOLOGY Carles Egusquiza Bueno IES Rocagrossa – Lloret de Mar 24 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.

26 Simple machines TECHNOLOGY Carles Egusquiza Bueno IES Rocagrossa – Lloret de Mar 25 Simple machines Inclined planeLever Screw Wedge Wheel and axle Pulley 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.

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

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

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

30 Simple machines TECHNOLOGY Carles Egusquiza Bueno IES Rocagrossa – Lloret de Mar 29 FRAGILE m b = 280 kg L F m m = 70 kg

31 Simple machines TECHNOLOGY Carles Egusquiza Bueno IES Rocagrossa – Lloret de Mar 30 FRAGILE m b = 280 kg L F L 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) m Mass of the man. Unit to measure mass: KILOGRAM (kg) F Force we have to apply to move the object. It can also be called effort or input force. Unit to measure force: NEWTON (N) m m = 70 kg mbmb Mass of the object we want to move. Unit to measure mass: KILOGRAM (kg)

32 Simple machines TECHNOLOGY Carles Egusquiza Bueno IES Rocagrossa – Lloret de Mar 31  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: FRAGILE m b = 280 kg L F m m = 70 kg

33 Simple machines TECHNOLOGY Carles Egusquiza Bueno IES Rocagrossa – Lloret de Mar 32 FRAGILE m b = 280 kg L = 1692 N F = 686,7 N m m = 70 kg  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). MA = 4

34 Simple machines TECHNOLOGY Carles Egusquiza Bueno IES Rocagrossa – Lloret de Mar 33 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

35 Simple machines TECHNOLOGY Carles Egusquiza Bueno IES Rocagrossa – Lloret de Mar 34 No, simple machines do not multiplying energy but force. 1.Do simple machines multiply energy? FRAGILE m b = 280 kg L = 1692 N F = 686,7 N m m = 70 kg MA = 4 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%. 2.What’s the relationship between the input energy and the output work of an actual machine? Why? W input > W output 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%. 3.What’s the relationship between the input energy and the output work of an ideal machine? Why? W input = W output

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

37 Simple machines TECHNOLOGY Carles Egusquiza Bueno IES Rocagrossa – Lloret de Mar 36 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.

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

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

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


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