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Force, Motion, & Simple Machines

FORCE, MOTION, & SIMPLE MACHINES

S4P3. Students will demonstrate the relationship between the application of a force and the resulting change in position and motion on an object.
a. Identify simple machines and explain their uses (lever, pulley, wedge, inclined plane,
screw, wheel and axle).

b. Using different size objects, observe how force affects speed and motion.

c. Explain what happens to the speed or direction of an object when a greater force than the initial one is applied.

d. Demonstrate the effect of gravitational force on the motion of an object.

PART 1: FORCE, SPEED AND MOTION

To make something move, you have to apply a FORCE to it; your hand, foot, a car, etc., a force is simply a push or a pull.  When you apply a certain amount of force to an object, it moves.  You have changed the object's position.  When the object was moving, it was in motion.

Forces can change the position and motion of an object.  If an object isn't moving, a force makes it start moving.  The object will move in the same direction as the force acting on it.  For example, if you kick a soccer ball, the ball will move in the same direction that your foot was moving.

Bigger objects that have more mass require that you push/pull with more force, because larger objects have more inertia.  This also means that a large object in motion will require more force to slow/stop it, because it has more inertia.  This is why when you kick a soccer ball, it goes much further than if you kick a bowling ball.  (PS, don't kick a bowling ball.  Trust me.  The inertia is a paaaaain.)

PART 2: GRAVITY AND FRICTION

Gravity is a force of nature that occurs in every object in the universe that has mass.  That's right, YOU have gravity, your dog has gravity, even the booger in your brother or sister's nose has gravity!  Gravity doesn't simply pull things "down," although it feels that way because that's all you've ever felt it do.  But you feel the pull of Earth's gravity because the mass of Earth is SO, um, "massive."

PART 3: SIMPLE MACHINES

MACHINE is anything that helps us do WORK easier (meaning anything that helps us do work with less FORCE).  The most basic machines are known as SIMPLE MACHINES.   There are several different types of simple machines:

LEVER

PULLEY

WHEEL & AXLE