Tuesday PS Notes 11-6

Homework

Conservation of energy

Homework

• Handout

Equation review on P1 prob 1-7

Energy Review on P2 prob 1-9

KE = ½mv2 GPE = mgh

m = mass (kg) g = acceleration (9.8)m/s2

v = velocity (m/s) h = height (m)

Description of 2nd rube

• Flame from lamp (A) catches on curtain (B) and fire department sends stream of water (C) through window.

• Small Man (D) thinks it is raining and reaches for umbrella (E), pulling string (F) and lifting end of platform (G).

• Iron ball (H) falls and pulls string (I), causing hammer (J) to hit plate of glass (K).

• Crash of glass wakes up pup (L) and mother dog (M) rocks him to sleep in cradle (N), causing attached wooden hand (O) to move up and down along your back.

Simplified Pencil Sharpener

Pencil Sharpener description

• Open window (A) and fly kite (B). String (C) lifts small door (D) allowing moths (E) to escape and eat red flannel shirt (F).

• As weight of shirt becomes less, shoe (G) steps on switch (H) which heats electric iron (I) and burns hole in pants (J).

• Smoke (K) enters hole in tree (L), smoking out opossum (M) which jumps into basket (N), pulling rope (O) and lifting cage (P), allowing woodpecker (Q) to chew wood from pencil (R), exposing lead.

• Emergency knife (S) is always handy in case opossum or the woodpecker gets sick and can't work.

Safety device for walking on Icy pavement

Icy Device Description

• When you slip on ice, your foot kicks paddle (A), lowering finger (B), snapping turtle (C) extends neck to bite finger, opening ice tongs (D) and dropping pillow (E), thus allowing you to fall on something soft.

How to keep a shop window clean

Description for shop window

• Passing man (A) slips on banana peel (B) causing him to fall on rake (C).

• As handle of rake rises it throws horseshoe (D) onto rope (E) which sags, thereby tilting sprinkling can (F).

• Water (G) saturates mop (H). • Pickle terrier (I) thinks it is raining, gets up to run into

house and upsets sign (J) throwing it against non-tipping cigar ash receiver (K) which causes it to swing back and forth and swish the mop against window pane, wiping it clean.

• If man breaks his neck by fall move away before cop arrives.

For each Picture!• Break down each Rube Goldberg Machine into a list of action in

sequence

• For each action, list any type/form of energy that is associated with the action

• For each energy type/form, state whether it is gained or lost as a result of the action

• Describe any simple machines associated with the action. For all machines, indicate input and output force

• For your favorite rube, list all objects that undergo work. Name the force which does work on object. Indicate which object had the most work done on it

Steps and energy connectionsSteps KE GPE EPE CE OTH

Kicking Paddle

Lowering finger

Turtle extending head

Tong separation

Dropping pillow

Draw arrow for each in each energy box, indicating if that type of energy is increasing because of action.

Steps and simple machines

Steps Type of Machine

Input Force

Output Force

Kicking Paddle Man’s leg

___ lever

Muscle Leg on Paddle

Lowering finger

Turtle extending head

Tong separation

Dropping pillow

Steps and energy connectionsSteps KE GPE EPE CE OTH

Draw arrow for each in each energy box, indicating if that type of energy is increasing because of action.

Steps and simple machines

Steps Type of Machine

Input Force

Output Force