Forces
  1. Is either a push or pull.

  2. A force can do the following

  3. >change the shape or size of an object

  • Ping_Pong_Ball_Cannon[2].jpg

>cause an object to change directions
imagesCAZBSRG1.jpg

Examples of a pull

imagesCAVZ1SZG.jpg

imagesCAQCRT12.jpg


Examples of a push


imagesCAHBUJN4.jpg

push_cart.jpeg

>Forces exist all around us all the time.

>Gravity is the force that pulls objects towards earth.


Example of a push and pull

forces_1.jpg


forces can also stop or slow down a moving object
external image forces.gif

There are 4 main types of forces

  • Elastic spring force
Is the force exerted on a spring when it is stretched/compressed
external image crossbow-elastic-potential.gif
  • Gravitational force
Is the force of attraction between Earth and other objects (e.g. me n Earth)
external image images?q=tbn:ANd9GcR4jVhefY501pgfBOQ5ngJqtrBfBiVrM3pI_Q2m62unHOUZphJ2
  • Magnetic force
Is the force of attraction and repulsion exerted by a magnet
external image images?q=tbn:ANd9GcS-XLBSFXywGw9_fybZtjr7EtwPwtAf-XpqibbRBovrv4L2Mtq5-A
  • Frictional force
Is the force that opposes motion
external image mfln125l.jpg
Pictures adopted : Google images

A force is any influence that causes a free body to undergo a change in speed, a change in direction, or a change in shape. Force can also be described by intuitive concepts such as a push or pull that can cause an object with mass to change itsvelocity (which includes to begin moving from a state of rest), i.e., to accelerate, or which can cause a flexible object to deform. A force has both magnitude and direction, making it a vector quantity.Example:

File-Force_examples.svg.png
File-Force_examples.svg.png
(picture from wikipedia)

More info about forces

If you are pulling or pushing exactly level to the ground, both ways take same force.  But usually, one or the other takes less force, because
one way tends to shove the thing you're moving into the ground (making
it harder to move) and the other way tends to lift the thing up.  So if
you are moving a sled, for example, it is easier to pull; but if you are
moving
something taller than you, it is usually easier to push.
 
Note : Info above taken from this website - [[http://www.newton.dep.anl.gov/askasci/phy00/phy00904.htm]]
 
 

external image Deep-Groove-Ball-Bearings.jpg
Ball bearings reduce friction between 2 surfaces. For our Interactions activity about the ball bearings, we see that the ball bearings allow the book to spin faster and more easily. Ball bearings are found in many things. Here are some examples:
1. Bicycle
2. A door.