Force, Motion & Energy SOL 4.2

The student will investigate and understand characteristics and interaction of moving objects. Key concepts include  motion is described by an object ’ s direction and speed;  forces cause changes in motion;  friction is a force that opposes motion; and  moving objects have kinetic energy.

Objects

’

Positions (Relative Location)

 “ The position of an object can be described by locating it relative to another object or to the background.

”  Example: The Oil is in front of the windmills. The Worker is beside the oil.

Showing Movement

 “ Tracing and measuring an object ’ s position over time can describe its motion.

”   Use Graphs to

60

show your data.

50

Example: I dropped

40

a ball three times

30

and measured the

20

height of each bounce.

10 Try 1 Try 2 Try 3 0 1st Bounce 2nd Bounce 3rd Bounce 4th Bounce

SPEED

 “

Speed

moving.

” describes how fast an object is  Example: The Police Officer Clocked the Driver going 68 MPH down the highway.

Types of Energy

 “ Energy may exist in two states: kinetic potential .

or 

Kinetic Energy

is the energy of motion.

” 

Potential Energy

is stored energy.

Kinetic energy is energy of motion.

Potential energy is converted into kinetic

energy. Before the yo-yo begins its fall it has stored energy due to its position. At the top it has its maximum potential energy. As it starts to fall the potential energy begins to be changed into kinetic energy. At the bottom its potential energy has been converted into kinetic energy so that it now has its maximum kinetic energy.

FORCE

 “ A

force

is any push or pull that causes an object to move, stop, or change speed or direction.

”  Example: this wagon can be pulled, pushed, stopped, and have it ’ s direction changed by a person.

Force

–

Easy or Difficult

Easy     “ The greater the force, the greater the change in motion will be. The more massive an object, the less effect a given force will have on the object.

Meaning Light Load – ” Lighter objects take less energy to move/change. Heavier objects take more energy. The Greater the Force used the quicker or easier the object will move. The Lesser the Force used the slower or harder the object will move.

Heavy Load Harder Heavy Load – Lots of Energy – YES Moving Heavy Load – No Energy – NO Moving

ROUGH SMOOTH

Friction



“

Friction

is the resistance to motion created by two objects moving against each other. Friction creates heat.

”  Friction is what will make moving something harder: texture of surface, elevation of surface, weight of object.

 Friction tries to STOP or SLOW an object.

 The Smoother or Flat the LESS Friction. The Steeper and Rough the MORE Friction.

FLAT HILLY

Moving?

 “ Unless acted on by a force, objects in motion tend to stay in motion and objects at rest remain at rest.

”  If no person, animal or natural event happens things will stay the same; either moving or still.