Wednesday, 10/22/14

1
Wednesday, 10/22/14

• 1) Two forces pull on a 5 kg object. Gravity
  pulls straight down, while the other pulls up and
  to the right at an angle of 80o, with a force of
  52 N. What is the net force in both the x and y
  directions?

2
Word Wall

• 8) Component (n) a part or element of a larger
  whole
• Example Forces at an angle have both x and y
  components.

3
Car in a Ditch Problem

• Teenagers are notoriously bad drivers. One day
  you are driving down a country road in a wooded
  area, and you make the critical mistake of
  texting while driving. Due to your lack of
  attention to the road, you run your car into a
  ditch. Luckily, you are unhurt, but your cell
  phone was smashed during the wreck, and you are
  alone and in the middle of nowhere, with no way
  to call for help. Your car still runs, but it is
  stuck in the ditch. You search your trunk, but
  find only a steel cable. The only thing you can
  tie the cable to other than your car is the
  surrounding trees. Is it possible to use this
  cable to pull your car out of the ditch all by
  yourself? Justify your answer using forces and
  force components.

4
Car in a Ditch Demonstration

• 1) What happens to the two people when a small
  force is applied perpendicularly to their force?
• 2) Explain why this happened using forces and
  force components.

5
Car in a Ditch Problem

• Apply what we just learned about forces and force
  components to the Car in a Ditch problem.
  Explain how you could potentially use the cable
  and the surrounding trees to move your car, and
  prove your answer using forces and force
  components.

6
Exit Ticket

• Aaron Rodgers uses a rope to pull a tank behind
  him at a constant velocity. If someone much
  weaker than him comes along and pulls sideways
  (perpendicularly) on the rope, what will happen
  to Aaron Rodgers motion?
• His motion will not change.
• He will slow down, but not change direction.
• He will begin to move sideways.
• He will speed up.

7
Wednesday, 10/22/14 (Enrichment)

• 1) Is it better for your bridge to be wide, or
  narrow? Explain your answer.