Force and Motion A LOOK AT THE NATURE

Force and Motion A LOOK AT THE NATURE OF ENERGY

What is Force? �A force is a push or pull. �A force may give energy to an object, creating motion, stopping motion, or changing its direction.

Types of Forces �Friction �Gravity �Air Resistance �Magnetism

Friction � Friction is a force that opposes motion. It stops or slows something down. When matter rubs against each other, it creates friction. � Friction works in the opposite direction of the force. � Friction also creates heat. If you kick a soccer ball in a grassy field, the friction in the ground stops or slows the ball down.

Gravity � Gravity is a force of attraction that exists between all objects in the universe. � What goes up, must come down! Gravity forces all objects to the center of the earth. Including us. Gravity helps us to be able to stand. � The size of the force of gravity depends on the mass of a object. The greater the mass, the greater the force of gravity.

Gravity �Think about it? If two objects of different masses are dropped from the same distance, which object will hit the ground first? Example: a watermelon and an apple?

Air Resistance � Air resistance- friction in the air. The rubbing of air molecules can slow down an object. � Drag is also called air resistance. Planes and racecars experience this. The air slows them down.

Magnetism �Magnetism is an invisible force that pulls certain substances towards a magnet. Not only is magnetism a fascinating natural phenomena, The Earth is a very big magnet. Its North and South poles are highly magnetic, but not very strong.

Balanced and Unbalanced Forces

Law of Conservation of Energy �The law of conservation of energy states that energy can neither be created nor destroyed by ordinary means. When we use energy, it doesn’t disappear. We change it from one form of energy into another.

Measuring Motion �Motion involves a change in position during a certain amount of time. �The rate at which an object moves is speed. Any object that is changing its position has speed. �Speed that does not change is called constant speed.

Velocity and Acceleration �Speed only describes how fast an object is moving, whereas velocity gives both how fast and in what direction the object is moving. �Acceleration is the rate of change in velocity. � An object speed up is positive acceleration. �An object slowing down is negative deceleration.

Momentum �Momentum describes how strong a moving thing is. �Things that aren't moving have no momentum. �Moving things have less momentum if they are light or moving slowly, and more momentum if they are heavy or moving fast.

Force and Motion Games/Websites � http: //www. gamequarium. com/forcesandmotion. html � http: //phet. colorado. edu/en/simulation/forces-and-motion-basics � http: //www. bbc. co. uk/schools/scienceclips/ages/6_7/forces_movement. shtml � http: //sciencegames. 4 you 4 free. com/force_motion_gravity. html � http: //studyjams. scholastic. com/studyjams/science/forces-and� � motion/force-and-motion. htm http: //studyjams. scholastic. com/studyjams/science/forces-andmotion/fgravity-and-inertia. htm http: //studyjams. scholastic. com/studyjams/jams/science/forces-andmotion/acceleration. htm http: //studyjams. scholastic. com/studyjams/science/forces-andmotion/action-and-reaction. htm