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 show your data. Example: I dropped a ball three times and measured the height of each bounce.

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

Types of Energy “Energy may exist in two states: kinetic or potential. 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 Heavy Load – Lots of Energy – YES Moving “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 – 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 – No Energy – NO Moving Light Load - Easy Heavy Load - Harder

ROUGH Friction SMOOTH “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.