GO UP, GO DOWN, PUSH ME, AND THROW ME AWAY 5-5.1 Illustrate the effects of force (including magnetism, gravity, and friction) on motion. Alfonso Landa

MOVEMENT In our world it is possible to see that things, animals, people… are moving. How can we know that something is moving? Something is moving because it is changing from one position to another over time. But why is it moving? What makes it moving? ©Microsoft Clipart ©pro.corvis.com

FORCES What make something move is the force. Force is any push of pull from one object to another. Some forces occur when one force touches another, such as a leg kicking a ball. Other forces, though, may act without object touching as a compass needle. ©Microsoft Clipart

EFECTS OF FORCE There are different effects of forces. They can: push or pull things forward (thrust) rise objects (lift) slow down the object or pull back, pull down. can crush, stretch Twist objects and deform them.

DIFFERENT FORCES An animal An engine Gravity Magnetism Natural forces There are different forces that make things move: An animal An engine Gravity Magnetism Natural forces Friction ©Microsoft Clipart

What goes up, must come down GRAVITY What goes up, must come down Gravity depends on their masses of the objects and the distance between them. Increasing the mass increases the force, and increasing the distance decreases the force. Every object in the universe is pulling on every other object because it has mass (Newton’s Law of Universal Gravitation). ©Microsoft Clipart

FRICTION Friction is a force that opposes the motion of one object moving past another. Friction makes difficult to slide on rough surfaces. Friction depends on: The surfaces How hard the objects are pushed together. To reduce friction we use lubricants ©Microsoft Clipart

MAGNETISM Magnetism is the ability of an object to push of pull on another object that has the magnetic property (iron, nickel). Magnets have two poles: north (N) and south (S), Like poles repel one another; different poles attract. www.howstuffworks.com/compass.htm

INERTIA Inertia is that an object at rest tends to stay at rest, and an object in constant motion tends to stay in motion, unless acted upon by an unbalanced forces. (Newton’s First Law) ©Microsoft Clipart Balance forces are forces that act on an object without changing its motion. The forces acting on stationary objects are always balanced. A force that causes an object to change its motion is called an unbalanced force.

FORCE, MASS AND ACCELERATION The unbalanced force on an object is equal to the mass of the object multiplied by its acceleration: F= m x a. (Newton’s Second Law) ©Microsoft Clipart Something that is accelerating, changing its speed, is because an unbalance force is acting in it. Acceleration decreases as mass increases as long as force is no changing.

ACTION REACTION All forces occur in pairs, and these two forces are equal in strength and opposite in direction. (Newton's Third Law) ©Microsoft Clipart When one object pushes on a second object, the second pushes back on the first with the same strength. When a person sits on a chair, the weight is pushing down on the chair. A reaction force from the chair pushes back up on the person.