## Our Taco Making Rube Goldberg

When we began this project we knew very little about what a rube Goldberg was. We had to create a rube Goldberg that had the minimum of 15 different steps and had had to run for at least 15 seconds. At the end of the rube it had to complete a task and our task was to make a taco. Our rube was successful and had 20 different steps and lasted 17 seconds. Before the exhibition we had to do a reliability check and it failed so we worked on it over the weekend and by the time we finished it worked three out of three times working better then most rubes at the exhibition. For eight different spots on our rube we had to calculate things like momentum, velocity, and transfer of energy, etc.

## Calculations-

**Calculation 1:**

Velocity from video for first ball bearing going down pink ramp.

Velocity= m/s

Length of ramp= 16 cm

Time= 0.32s

Velocity= 0.16m/0.32s

Velocity= 0.5m/s

**Calculation 2:**

Conservation of momentum, transfer of energy from the first ball bearing to the glass marble.

Conservation of Momentum= m1v1=m2v2

Mass of first marble(m1)= 0.1635 kg

Mass of second marble(m2)= 0.00599kg

Velocity of first mable(v1)= 0.5m/s

Conservation of moment= (0.1635kg)(0.5m/s)=(0.00599kg)(v2)

Conservation of Momentum(v2)= 13m/s

**Calculation 3:**

Potential energy of the second silver marble in the first pulley.

Potential Energy= m•g•h

Mass of marble= 0.00189 kg

Gravity= 9.8 m/s2

Height= 0.07m

Potential Energy= (0.00189 kg)(9.8 m/s2)(0.07 m)

Potential energy= 0.001 J

**Calculation 4:**

Impulse of the domino connected to a card hitting the blue marble.

Impulse=F∆t=Pf-Pi

Change in time(∆t)=0.05s

Final momentum= (0.0059kg)(0.375m/s)

Initial momentum= 0 kg*m/s

Force in Newtons= 0.0022(Pf)-0(Pi)/0.05s(∆t)

Force in Newtons= 0.044 N

**Calculation 5**:

Power of the swing.

Power= w/t

Work(w)= 0.036 J

Time(t)= 0.16s

Power= 0.036 J/0.16s

Power= 0.23 W

**Calculation 6:**

Momentum of the swing.

Momentum= m•v

Mass(m)= 0.00574 kg

Velocity= 1.7m/s

Momentum= (0.00574kg)(1.7m/s)

Momentum= 0.01kg•m/s

**Calculation 7:**

Kinetic energy of the truck.

Kinetic Energy= ½ mv2

Mass= 0.0094 kg

Velocity= 0.23

KE= ½ (0.0094 kg)(0.23 m/s)2

KE= 0.0024 J

**Calculation 8:**

Velocity of the truck going down the ramp.

Velocity= d/t

Distance= 0.2 m

Time= 0.88 s

Velocity= 0.2m/0.88s

Velocity= 0.23 m/s