2. What is work? Work = when you exert a force on an object and that object moves some distance The force must be in the same direction as the object’s motion Work = force x distance (measured in Joules) To help rearrange the furniture in your class, you exert a force of 20 N to push a desk 10 m. How much work did you do?

3. Machine Change the size and direction of a force Makes work easier or faster Input force – the force you exert Output force – the force exerted by the machine NEVER give out more than is put into them

4. Simple Machines Does work with one movement. Mechanical Advantage – compares the input force to the output force

5. Inclined Plane A slanted surface used to raise an object. Work is made easier by using less force over a greater distance. - the longer, less steep = less work Example wheel chair ramp

6. History of Inclined Plane Thought to have been used to build the Great Pyramids

7. Wedge A moving Inclined Plane The “sharper” the wedge, the greater the mechanical advantage. Longer and thinner wedges = less input force Example - axe

8. Screw An inclined plane wrapped around a cylinder. It is easier to gradually work up a slope than to go straight up The closer the pitch on a screw, the greater the mechanical advantage. Example – jar lid

9. Lever A bar which can freely move around a fixed point or a fulcrum. There are three types of levers (types depend on the location of the fulcrum, input force and output forces):

10. Input force = Effort Output Force = Load

11. First-Class Lever The fulcrum is between the Input force and the Output force Changes the size and direction of the input force

12. First-Class Lever – See Saw Other examples – scissors and pliers

13. Second class lever The output force is between the fulcrum and the Input force. Multiplies the output force, but does not change its direction.

14. Second class lever Other examples: doors, nutcrackers, bottle openers

15. Third class lever The Input force is between the fulcrum and the output force Multiplies the distance Does not change direction of input force

16. Third class lever – baseball bat Other examples – fishing poles, shovels, rakes, brooms

17. Pulley A belt, rope or chain wrapped around a wheel There are –Fixed pulleys (pulley can not move – flag pole) –Movable pulleys (pulley can move along rope - zip line) –Pulley Systems (multiple pulleys working together – weight machines)

18. Wheel and Axle 2 circular objects that are fastened together and rotate around a common axis The larger object is the wheel – the smaller wheel is the axle Examples – door knob, screwdriver, steering wheel