Exercise 2 Can you identify the basic parts of a steam machine? Complete the boxes using the appropriate words from the grey box.

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1 cams & cranks Exercise 1 Complete the boxes using the words in the grey box. (points 2,5) cam, follower, guides, stroke, shaft Exercise 2 Can you identify the basic parts of a steam machine? Complete the boxes using the appropriate words from the grey box. (points 2) connecting rod, cam, piston, crank, crown, flywheel, torque Exercise 3 Correct the following paragraph about the cranks by circling the correct word in each case. (points 2) The first use of a crank was as a lever / handle in order to rotate / lift things, achieving rotational / lifting motion. The crank is a device / mechanism used to convert lifting / rotational motion to reciprocal / rotational, as we have observed in the pumpjack model. In order to turn the crank easily, its handle / pulley should be positioned far away from / near to the axle that produces the output movement.

2 cams & cranks Exercise 4 Join the names of cam profiles with the correct pictures (indicated with numbers) (points 3) 1 triangular cam drop or snail cam 4 2 round cam heart-shaped cam 5 3 linear cam pear- or egg shaped cam 6 Exercise 5 Do you know the cam terminology? Put the correct names in each box. (points 3) follower fall stroke rise follower, fall, stroke, direction of rotation, rise, dwell

3 cams & cranks Exercise 6 A pepper grinder s crank has a radius (R) of 3 cm and a force (F) of 20 N* is applied on it. Can you calculate the Torque (T) created on the pepper grinder? (points 2,5) R F Pepper grinder *Newton (N) is the unit of measurement of force Newton meters (Nm) is the unit of measure of Torque Exercise 7 The following pictures demonstrate some examples of different types of motion: reciprocal, linear, oscillating and rotational motion. Can you identify them and write them correctly under each picture? (points 3) Newton s cradle Helicopter s propeller A saw An injection An exercising wheel for hamsters Car window wiper Exercise 8 Can you complete the names of the different types of followers, written in the grey box? (points 2) offset follower, roller follower, flat follower, point-knife follower

4 gears Exercise 1 Complete the sentences below using appropriate words from the grey box. (points 3) output speed, mesh, driver, between, driven, direction, reversed, maintain, bigger, idler gear When two gears... directly, the... of rotation is... If we want to... the same direction of rotation, an is needed, positioned... the other gears. In order to increase the the... gear should be... than the... gear. Exercise 2 Complete the diagram with the words in the grey box. (points 2) root, pitch circle, pitch, pitch point, tooth, circular thickness, pitch circle Exercise 3 In the right picture, you can see a standard gear train which transfers motion from the small gear to the big gear through the medium one (idler gear). Can you suggest a way to transfer the same motion without using an idler gear, while still keeping the same direction of rotation? Explain your idea and draw it in the box provided. (points 2) Exercise 4 Draw a two-gear system (with simple circles) where the output speed is increased by 5 times. Show for each gear the direction of rotation, indicative number of their teeth and their role in the gear system, driver or driven. (point 2)

5 gears Exercise 5 (a) Complete the following picture using the words in the grey box. Can you also show the direction of gears B and C with arrows? (point 1) idler gear, driver gear, diameter, driven gear A C (b) What is the purpose of the idler gear? (point 1) B Exercise 6 The following gear system consists of 4 gears. Gear A is the driver gear and has 80 teeth, gears B and D have 20 teeth and C has 40 teeth. A C a) Can you calculate the velocity ratio (V.R.) of this gear system? (points 2) D B b) If the diameter B is 200 mm, can you find the diameters (D) of gears A, C and D? (point 1) c) If gear D is rotating with 4000 rpm what is the speed of gear A? (point 1)

6 gears Exercise 7 Choose the correct names of the following gear types from the box and write them below each picture. Then choose the correct description on the right and write the appropriate numbers inside the small boxes (points 3) bevel gear, idler gear, worm gear gearbox, rack and pinion, chain drive 1 A gear train including one or more compound gears which significantly changes the speed of rotation (increase or decrease). 2 Converts rotational motion to linear. 3 Works only in one direction while it reduces the speed by a large amount. 4 Connects two gears (sprockets) that are not near while keeping the same direction of rotation. 5 Changes the direction of rotation by 90 degrees. 6 Maintains the same direction of rotation between the driver and driven gear. Exercise 8 Write down 1 similarity and 3 differences between pulleys and gears. (points 2)

7 levers Exercise 1 Fill-in the boxes with these words: load, effort, fulcrum. (point 1) What class is this type of lever? Exercise 2 Join the pictures with the correct sentences. (points 1,5) 1 First-class lever 2 Second-class lever 3 Third-class lever

8 levers Exercise 3 Below you can see various devices and tools which we use in daily life. Study the images carefully and write the class of each lever (first, second or third)). Then complete the little squares at the points where the effort is applied (write E), the load (write L) and the fulcrum (write F). (points 5,5)

9 levers Exercise 4 The opinions of the children about levers differ. With who do you agree and why? (points 2,5) When I use levers I can lift a larger amount of load than the force I use, but I have to travel a longer distance. When I use levers I can lift a large load with ease. I gain force from nothing! Angela Peter Haha! My little sister will not be able to lift me in the see-saw today! It s impossible to transfer motion from one point to the other when levers are used. In order to achieve this we have to use different machines. Andrew Matthew The bigger the distance from the fulcrum, the harder it is to lift the load. Jennifer I agree with... because

10 levers Exercise 5 Complete the gaps using the appropriate words from the grey box. (points 3,5) A... is a rigid rod (or bar) that rotates around a fixed point called... and is used for moving heavy objects easily. The object that we want to move is called..., while the force we apply, in order to move it, is called... load, first-class, second-class, big, fulcrum, gain, effort, third-class, lever, lose. By using levers, we can apply a small amount of effort in order to move a... weight. Attention though! What we... in force we... it in movement. Exercise 6 Andrew took his sister Debby to the playground. When they sat on the seesaw little Debby started crying, because she was constantly in the air and the seesaw did not work properly due to the weight difference. Hearing his sister crying, Andrew told her: Sit on the edge of your side and let me handle the rest! If Debby weighs 30Kg and sits in a distance of 150cm from the center of the seesaw (fulcrum), while Andrew weighs 90Kg, in what distance should Andrew sit in order to achieve balance? (points 3) Exercise 7 Study the next picture and comment in your own words the meaning of Archimedes phrase: Give me a place to stand on and I will move the Earth!. (points 3)

11 linkages Exercise 1 Circle the joints and show with arrows the rigid links of this linkage (points 3) Exercise 2 Join the pictures with the correct sentences (points 5) 1 Parallel motion linkage 2 Treadle linkage 3 Reverse motion linkage 4 Toggle linkage 5 Bell crank linkage

12 linkages Exercise 3 Complete the gaps using the appropriate words from the grey box. (points 3,5) joints, George, rigid links, movable, chain, mechanism, fixed, input, output, pulleys. A linkage is a series of... connected with... to form a closed or open... (or a series of them). A linkage is called a... if it has two or more rigid links that move in respect to a... rigid link. In order for a mechanism to work we need to apply a force or set to motion a certain point, which is called..., that will cause another point of the mechanism to move or produce a force, called... Exercise 4 B In the next pantograph, if the pencil is placed on point C and the tracker on point D, how many times larger will the copy image be than the original? (points 5) O R Distances: AB=40cm AO=10cm BC=40cm BR=10cm A D C Exercise 5 If we reverse the tracker and the pencil in the above pantograph (pencil in point D and tracker in point C), how many times smaller will the copy image be than the original? (points 3,5)

13 inclined planes & wedges Exercise 1 Complete the gaps using the appropriate words from the grey box. (points 2,5) length of plane, screw, thickness, lever, 60, wedge, 90, weight. An inclined plane is a surface - a plane - placed with an inclination (slope or tilt), of an angle less than... degrees on a horizontal surface. Two more simple machines are created from the inclined plane: the... and the.... The mechanical advantage of the wedge depends on its... and.... Exercise 2 Read the sentences below about the inclined plane and mark those that are correct. (points 2,5) With the help of an inclined plane we can transfer a heavy load in a shorter distance in relation to the distance needed if we would transfer the same load upright. The steeper the inclined plane, the more force is needed to carry a box. The wedge and the screw are in reality different forms of inclined planes. The steeper the inclined plane the longer its inclined side is. The inclined plane is not considered a simple machine. Exercise 3 What similarities do you see in the two pictures below? (points 3) Portable ramp on a truck Uphill road

14 inclined planes & wedges Exercise 4 Mark with a the devices that work on the principle of the inclined plane. (points 6)

15 inclined planes & wedges Exercise 5 In both cases below, 1 and 2, a worker tries to move a box up to a certain height with the help of a frictionless inclined plane. Draw the forces that are applied on the box in each case. (points 3) 1 2 Exercise 6 Answer the following questions concerning the drawings above (points 3) a) In which case does the worker apply more force in order to move the box? Why? b) In which case does the box cover a longer distance? Why? c) In which case do we need more work (energy)? Why?

16 pulleys Exercise 1 In the following pictures, the little mouse is trying to lift the elephant with the help of a pulley system, so its effort is reduced as much as possible. Explain which picture represents the right way of lifting the elephant! (points 2) A B Exercise 2 Complete the next diagram using the words in the grey box. (points 2,5) effort, load, rope, fixed point, pulley Exercise 3 The following pictures show three different pulley systems. Can you indicate with arrows the direction of motion of the follower pulley for each case? (points 1,5) A C B

17 pulleys Exercise 4 Both pictures depict Archimedes trying to pull a ship on to the shore. In picture A he uses two pulleys fixed on a tree, while in picture B he uses three pulleys, one fixed on a tree and two on the ship. Look carefully at the pictures and decide which way of using the pulleys is correct and why. (points 3) A B Exercise 5 Complete the sentences below that describe the 3 cases by choosing words from the grey box. Some of the words can be used more than once. (points 3) driver pulley, more, follower pulley, belt drive, equal to, greater than, less, big, small. A B C Two pulleys of the same diameter on parallel axles are connected by means of a... The left pulley is called... while the right pulley is the... The rotating speed of the left pulley is... the rotating speed of the other pulley. Two pulleys of different diameter on parallel axles are connected by means of a... The small pulley makes... revolutions than the bigger pulley. The big pulley is called... while the small one is called... Two pulleys of different diameter on parallel axles are connected by means of a... The driver pulley (... pulley) makes... revolutions than the... (small pulley).

18 pulleys Exercise 6 Four pulleys on three parallel axles (A, B, C) are connected by means of two belts. Both pulleys 2 and 3 are attached to the axle B. The diameter of pulley 1 is equal to the diameter of pulley 3 and the diameter of pulley 2 is equal to the diameter of pulley 4. Look carefully at the following diagram and answer the questions below. (points 5) 3 4 A 1 2 B C a) The speed of axle C is lower than, greater than or equal to the speed of axle B?... b) The speed of pulley 2 is lower than, greater than or equal to the speed of pulley 3?... c) Which axle of the three has the lowest speed?... d) Which pulley rotates with the greatest speed?... e) This mechanism is appropriate for reducing, increasing or keeping constant the speed of a pulley system.... Exercise 7 Make calculations in the space provided and write your results in the boxes. (points 3) (a) The following pulley system consists of one small driver pulley and a bigger follower pulley. The diameter of the driver pulley (D1) is 200mm and the velocity ratio of the system is 2. Can you find the diameter of the follower pulley? (b) The force applied on the rubber band is F1=F2=25N. Calculate the torque of both pulleys, Tinput and Toutput. D2 = D1 = F1 F2 Driver pulley Follower pulley Tinput = Toutput =

19 screws worm & drives Exercise 1 (a) Can you identify the basic parts of a screw? Complete the following picture using the words in the grey box. (points 1,5) thread, crest, head, length, pitch, nut, shank (b) Can you explain how a screw and a nut work together? (points 0,5) Exercise 2 Write down at least 4 of the major tools used to tighten the screws. (points 2) Exercise 3 Complete the diagram with the words in the grey box. Also, write under each box, which part of the worm drive is the driver and which the follower. Can you show with arrows the direction of each part? (points 2) axle, driver, worm, worm wheel, follower

20 screws worm & drives Exercise 4 A circular saw, similar to the one in the next picture, works by means of a worm drive where the worm rotates a worm wheel which is attached to the blade in order for the device to cut something. a) Can you calculate the gear ratio of the worm drive, if the worm wheel has 40 teeth? (point 1) b) What does your result actually mean about the speed of the worm drive? (points 2) Exercise 5 Complete the sentences below using appropriate words from the grey box. (points 3) worm gear, rotates, linear, nut, headless, rotational, cylinder, inclined plane, worm wheel. A screw is a... with an wrapped around its surface. Either as fastener or with a..., screw converts... motion into.... A... is actually a... screw which rotates a Exercise 6 The threaded length of the screw at right is 280 mm while the nut can travel only a distance of 40 mm. a) Can you calculate the mechanical advantage of this mechanism using the information above? (point 1) b) Having in mind the M.A. you have just found and that the diameter (D) of the screw is 5 mm, can you find the size of its pitch? (points 2)

21 screws worm & drives Exercise 7 Jennifer, Matthew, Angela and Andrew describe the types of screws. Can you write down in the boxes next to each description the name of the screw type they are referring to? (points 2) It has a flat end, no head and sometimes works in conjunction with a nut. It passes through a threaded hole of an outer object in order to be tightened against an inner object preventing any relative movement. It can be found in various sizes and different materials according to the surface we want to open a cylindrical hole on. It has a sharp end and it is used in order to fasten a piece of metal on a wooden surface. It has a flat end and it is used to fasten objects together that have holes in order to pass through. A nut is used to secure the two objects. Exercise 8 Connect each type of screw head with its name. (points 3) Slotted head screw Cross-shapped head screw Robertson s head screw External hexagon Square head screw head screw Internal hexagon head screw

22 wheels & axles Exercise 1 In the following pictures, James is moving the same load, but he uses a different trolley in each case. In which case do you think is easier to move the load and why? Complete the boxes below with the words easy or difficult and explain your choice in the space provided. (points 2) Exercise 2 Read the paragraph and erase the wrong words. (points 2,5) The bigger / smaller the wheel, the easier it is to move a vehicle. This happens because the wheel and axle mechanism works as a pulley / lever which rotates 180 / 360 degrees. Therefore, the bigger / smaller the radius of the wheel, or the bigger / smaller the radius of the axle, the less effort is needed for the vehicle to move. Exercise 3 Join the pictures with the correct sentences (2 for each picture). (points 3) 1 Easy effort 2 Medium effort 3 Difficult effort 4 Slow speed 5 Medium speed 6 Fast speed

23 wheels & axles Exercise 4 The opinions of the children about wheels and axles differ. With whom do you agree and why? (points 2,5) Friction does not affect the function of the wheel and axle mechanism. The size of the wheel is what matters the most. The size of the axle is not important. Angela Peter The wheel is considered a simple machine by itself. The wheel and axle mechanism is a simple machine capable of transferring and multiplying a force. This depends on the radii of the two. Andrew Matthew When wheels rotate freely, often the axle is connected with an engine or other mechanism. Jennifer I agree with... because

24 wheels & axles Exercise 5 Complete the gaps using the appropriate words from the grey box. (points 4) wheelbarrow, rotating, free rotation, supported by, car, separately, fixed on, together. There are two types of mechanisms of wheel and axle: fixed and..., which depend on the way that the wheel is... in respect to the axle. In the first case, the wheel is... the axle and they rotate... An example of such mechanism is the... In the second case, the wheel is... the axle and they rotate... An example of such mechanism is the... Exercise 6 Little John wants to move his toys from the living room to his bedroom using a small carrying cart. If the wheel s diameter is 20cm and the axle s diameter is 4cm, how much mechanical advantage will he gain? (points 3) Exercise 7 Most of the times friction wastes energy and is unwanted. In most machines with moving parts friction resists and slows down the motion, causing attrition and damaging the mechanisms in the long-term. Write down 3 ways to reduce friction. (points 3) (a) (b) (C)