Forces

1
Forces

• SOL 4.2
• (Information Used from www.solpass.org)

2
Force

• A force is a push or a pull.  Every time you push
  or pull something you use a force. Forces
  transfer energy.

3
Energy

• When you throw a ball, the force of your arm
  pushes the ball into the air. Energy is
  transferred from your arm to the ball.

4
Potential Energy

• Stored energy
• Energy on hold and ready to go

5
Push and Pull

• A pull that starts an object moving might be the
  pull of gravity or the pull of a magnet.  A push
  that starts an object moving might come from the
  wind or the muscles in your legs.
• Once it is moving it has kinetic energy.

6
Inertia

• An object in motion will stay in motion, until a
  force stops it.  The force stopping the object's
  motion might be an obvious one - the ground!
• An object at rest will stay at rest, until a
  force starts it moving.

7
Friction

• A less obvious force that stops or slows motion
  is friction.  Even air causes friction.  Friction
  is a force that prevents or stops motion. 
  Friction is the resistance to motion created by
  two objects moving against each other (the sled
  and the snow). Friction creates heat. (rub your
  hands together)

8
Mass and Inertia

• How a force affects an object depends on the
  object's mass.   The more massive an object, the
  less effect a given force will have on the
  object. More massive objects are said to have
  more "inertia". 

9
Quiz Time 1

• Which shoe tread would provide the most friction
  to keep you from slipping?
• A. --C.
• B. --D.

Correct Answer-A
10
Quiz Time 2

• Objects in motion have ______________ energy.
• A. Stored
• B. Kinetic
• C. Potential
• D. Negative

Correct Answer-B
11
Quiz Time 3

• Due to the pull of gravity, the higher an object
  is off the ground, the more _________________
  energy it has.
• A. Kinetic
• B. Electrical
• C. Chemical
• D. Potential

Correct Answer-D
12
Quiz Time 4

• When an apple is hanging on a tree it has
  potential energy. When it falls off the tree,
  potential energy changes to
• A. Chemical Energy
• B. Kinetic Energy
• C. Nothing
• D. Electrical Energy

Correct Answer-B
13
Quiz Time 5

• In order to move a piano that weighs 800 pounds,
  you will have to produce more or less force than
  moving a piano that weighs 400 pounds.

800 lbs
400 lbs
Correct Answer-more force
14
Quiz Time 6

• You are having a hard time getting a ring off of
  your finger. What could you do to reduce the
  amount of friction to help you remove the ring?
• A. Rub the ring with a cloth
• B. Have a friend pull as hard as they can
• C. Put baby powder on the ring
• D. Put oil on the ring

Correct Answer-D