Rube-Goldberg Device

1. Team 6 Nikki Arcamuzi Jordan Harris Kristen Rich’ard Tyler Stanley Rube-Goldberg Device April 28, 2010

2. Design • ball is placed at the end of a tube and held there by a piece of wood. • Group 5 removes wood • ball will be released and rolls down the tube until it elastically collides with another ball. This second ball is attached to a pendulum that rotates about its opposite end. • once the pendulum rotates, it strikes a third ball that will be resting on a platform. • The third ball projects through the air and goes into a funnel. It goes down the funnel and falls out onto a track. • The path of the track directs the ball to a mousetrap. • The mousetrap has two strings attached to it; One that pulls a piece of wood (which starts group seven’s project) and one that leads to a pull string to a lamp in order to turn it on.

3. Calculations Step 1 Translational motion Conservation of Energy to find velocity of ball at bottom of pipe h=.479 ft mgh=.5mv^2 gh=.5v^2 (32.2)(.479)=.5 v^2 v=5.56 ft/s Step 3 Projectile motion y = 0 y0 = 0 x0 = 0 x = .416 ft g = 32.2 v0 = 5.56 ft/s  trajectory equation theta = 11.7 degrees  Step 5 Free Fall Has an initial y velocity coming off of track of .726 ft/s         angle of track from horizontal 12.84 degrees         3.27sin(12.84)=.726 ft/s constant accleration equation to find final velocity (free fall) s2 = s1 + [(v2^2 - v1^2)/2a] 0 = .5 ft  + [(v2^2 - (.726)^2)/2(32.2) v2 = 5.63 Step 2 Rotational Motion v (from step 1) = 5.56 ft/s r = .458 ft w(omega) = v / r w = 5.56 ft/s / .458 ft w = 12.14 rad/s Step 4 translational motion conservation of energy h = .167 ft mgh=.5mv^2 gh = .5v^2 (32.2)(.167) = .5 v^2 v = 3.27 ft/s

4. Cost Wood = $4 PVC Piping = $2 Bouncy Balls = $1 Mousetrap = $1 Makeshift Funnel = $0.05 String = $0.50 Nails = $1 Glue = $0.50 Tape = $0.50 $10.55 The opportunity to spend extra hours on engineering projects: PRICELESS

5. Building Issues Our original design : a rotating cup was supposed to drop the final ball onto a power button of a cell phone or calculator.  Problem 1) Balls ending location too unpredictable.  Solution 1) We changed the rotating cup to a second PVC pipe and built a track so the ball would fall directly onto a mousetrap with strings attached.  One string to pull a piece of wood in order to start group seven's project, the other to pull on a lamp and turn it on. Problem 2)Incosistency of projectile ball going into funnel.  Solution 2)We trimmed the funnel until the ball went in everytime. Problem 3)Inconsistency of rolling bouncing ball hitting the mousetrap.  Solution 3)We build a track to force it towards the mousetrap.

6. Results • We had to change the original design, which was where a rotating cup dropped the ball onto the power button of either a cell phone or calculator. • The new design included using a second pvc pipe to drop the ball and the use of a track to allow the ball to fall off onto a mousetrap. The funnel used to drop the ball onto the track had to be trimmed down in order to make sure the ball would go in every time. • The mousetrap had strings attached so that when hit, one would start group seven’s project and one would turn on a lamp when pulled. Once we made these changes, the project worked well. • The collision of the first two bouncy balls caused the pendulum to hit the third bouncy ball, which thus went through the air into the funnel. Then the ball was funneled down onto the track and on a path towards the mousetrap. • When the ball hit the mousetrap it turned on the lamp and would start group seven’s project.