WHAT IS INERTIA The behavior of all objects

WHAT IS INERTIA? The behavior of all objects can be described by saying that objects tend to "keep on doing what they're doing" (unless acted upon by an unbalanced force). n If at rest, they will continue in this same state of rest. If in motion with an eastward velocity of 5 m/s, they will continue in this same state of motion (5 m/s, East). n If in motion with a leftward velocity of 2 m/s, they will continue in this same state of motion (2 m/s, left). n. The state of motion of an object is maintained as long as the object is not acted upon by an unbalanced force. n. All objects resist changes in their state of motion - they tend to "keep on doing what they're doing. " n

Mass n n n …is measured in kilograms. …is the measure of the inertia of an object. Inertia is the natural tendency of a body resist changes in motion.

Force n …the agency of change. n …changes the velocity. n …is a vector quantity. n . . . measured in Newton’s.

2 -7. First Law of Motion The first law of motion states: If no net force acts on it, an object at rest remains at rest and an object in motion remains in motion at a constant velocity.

a=F/m

FREE FALL n n In the absence of air resistance all bodies fall with the same constant acceleration. Object in free fall near the surface of Earth has an acceleration of 9. 8 ms-2

2 -5. Free Fall The acceleration of gravity (g) for objects in free fall at the earth's surface is 9. 8 m/s 2. Galileo found that all things fall at the same rate.

2 -6. Air Resistance n In air… • A stone falls faster than a feather n n Air resistance affects stone less In a vacuum • A stone and a feather will fall at the same speed.

Mass Vs Weight n n n Mass is not the same as weight. Mass is a measure of an objects inertia Mass is measured in grams &Kilograms Weight is an amount of gravitational force acting on an object W=mg Weight is measured in Newton

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