Bell Work: 3/26/12

1
Bell Work 3/26/12

• Write about something scientific you did over
  spring break.

2
TCAP Practice Book

• Complete Part I of the science section pgs.
  1-35.
• Answer each question. You will have 30 minutes.
• Discuss answers and justify your answers. Explain
  next to the question the answer choice is
  correct.

3
Bell Work 3/27/12

• Hannah just finished building a house of cards
  that stands four-stories high. She is worried
  that it will fall down.Which of the following
  statements is definitely true?
• A house of cards is too fragile and must fall
  down eventually.
• If Hannah adds another card to the house of
  cards, then it will fall down.
• If no unbalanced force acts upon the house of
  cards, then it will remain standing forever.
• As long as nobody touches the house of cards, it
  will remain standing.

4
Objectives

• Identify and explain how Newtons laws of motion
  relate to the movement of objects (SPI
  0707.11.4).

5
Newtons First Law of Motion
An object at rest remains at rest, and an object
in motion remains in motion at a constant speed
and in a straight line unless acted on by an
unbalanced force.

• Net force combination of all of the forces
  acting on an object
• When net force is 0 N, the forces are balanced.
• When the net force on an object is not 0 N, the
  forces on the object are unbalanced.
• Newtons first law of motion is sometimes called
  the law of inertia.
• Inertia is want to, when an object resists
  change because it wants to keep going in a
  straight line.
• Inertia depends on an objects mass.
• The more mass an object has, the more inertia an
  object has.

6
Money Going Nowhere
7
Newtons Second Law of Motion
The acceleration of an object depends on the mass
of the object and the amount of force applied.

• Weight vs. Mass
• Weight is a measure of gravity on an object.
• Mass is the amount of matter (what an object is
  made of) in an object.
• F (force) m (mass) x a (acceleration)
• F m x a
• a (acceleration) F (force) m (mass)
• a F m
• If you want to increase the acceleration of an
  object, you need to decrease its mass.

8
Dinner Anyone?
9
Newtons Third Law of Motion
For every action there is an equal and opposite
reaction.

• Newtons third law can be simply stated as
  follows All forces act in pairs.

10
Bell Work 3/27/12

1. What is friction?

11
Question

• Why do you think the sponge shown below has a
  layer of plastic bristles attached to it?

12
Relate the Diet Coke and Mentos demonstration to
Newtons 3rd Law.
13
Film Canister Rockets
14
Momentum

• Imagine a compact car and a large truck traveling
  with the same velocity. The drivers of both
  vehicles put on the brakes at the same time.
  Which vehicle will stop first?
• The car because a larger force is needed to stop
  the truck. The truck has more momentum because it
  has more mass.
• The momentum of an object depends on the objects
  mass and velocity. The more mass an object has,
  the more momentum it has.

15
Work Order

1. Word Problem Newtons Laws Sheet
2. Extra Credit
3. Study Island Force Motion
4. Study Guide