1. RUBE GOLDBERG: PETTING A DOG By: Kaily, Sam, Erin, and Emily, group 2, period 10

2. PETTING A DOG  Sam created the initial design. After that we all added our own input.  The inspiration came from structures he sees at the farm.  It contains at least 1 of every simple machine and certain kinds like the incline plane are used multiple times.  The goal we achieved was to successfully pet a dog

3. PETTING A DOG  The machine starts off with by pushing a small car into dominoes  The domino is a 3 rd class lever  The MA for a domino is 0.22 Le= 1cm, lr= 4.5cm MA=le/lr MA=1cm/4.5cm

4. PETTING A DOG  Then the dominoes hit balls which slide down a ramp.  The ramp is the 1 st inclined plane  The MA for the inclined plane is 1.4 l= 25cm, h= 18cm, MA= l/ h, MA= 25cm/18cm

5. PETTING A DOG  After the inclined plane the balls roll down into the funnel. Balls exit funnel onto another ramp.  MA for the 2 nd inclined plane is 3.4 l= 17cm, h=5cm, MA= l/ h, MA=17cm/5cm

6. PETTING A DOG  At the end of the ramp the balls drop into a screw.  MA for the screw is 0.4 circumference=1.6ft pitch=4 MA= circumference/pitch, MA= 1.6ft/4ft

7. PETTING A DOG  Balls drop out of screw and are separated by a wedge.  MA for a wedge is 0.4 h=4cm, b=10.5cm, MA=h/b MA=4cm/10.5cm

8. PETTING A DOG  Wedge leaves 1 ball to travel down a ramp.  The MA for the 3rd inclined plane is 2.7 l= 32cm, h=12cm MA= l /h MA=32cm/12cm

9. PETTING A DOG  At the end of the ramp is a pulley system  The MA of the pulley system is 1 Number of support strings=1

10. PETTING A DOG  Ball is released from pulley system and hits a domino  This pushes the yo-yo  MA for wheel and axle is 0.2 axle radius= 0.5cm wheel radius= 3cm MA=axle radius/wheel radius MA=0.5cm/3cm

11. PETTING A DOG  Yo-yo releases the piece of wood holding up the hand that will pet the dog.

12. PETTING A DOG Total simple machines  Levers= dominoes  Pulley System = cup pulley system  Wedge = separator  Inclined Planes = 3 ramps  Screw = spiral ball travels down  Wheel and axle = yo-yo