2. Newton’s First Law of Motion

3. Newton’s First Law of Motion What it says: An object at rest will remain at rest and an object in motion will remain in motion at constant speed and in a straight line unless acted on by an unbalanced force.

4. What it means: Unless you apply force to a stationary object it will not move. Likewise, unless force is applied to a moving object it will not stop moving nor will it change directions. It tends to do what it was doing unless force is applied to it. What it means: Unless you apply force to a stationary object it will not move. Likewise, unless force is applied to a moving object it will not stop moving nor will it change directions. It tends to do what it was doing unless force is applied to it

5. How does motion occur? In order to understand how motion occurs you must first understand what force is. FORCE is an action that has the ability to change motion. I you were asked to move your desk to another place in the room, how would you do that? Most of you probably are saying pick it up and carry it, drag it across the room, or push it across the room. In using any method to move the desk, there are only two ways in which force can be applied to the desk to cause it to move. What are they? You either PUSH IT or PULL IT.

6. The metric unit for force is the Newton. 1 N = 1 kg x 1 m/sec 2 This means that a force of 1 N will cause a 1 kg mass to accelerate at a speed of 1 m/sec 2 Unless force is applied to an object, that object will never move. This force must be in sufficient quantity or strength to overcome the mass of the object that is being moved. Nothing moves on its own. The force must over come the force of friction. Unless the bowling ball strikes the pins, they will never move.

7. Balanced Forces: The forces on an object are equal in size but opposite in direction; will not change the objects velocity. Ex) A tug of war when no team is winning.

8. Unbalanced Forces: Occur when one force on an object is stronger than another; will change an objects velocity. Ex) A tug of war when one team is winning.

9. Friction is the force that opposes the sliding motion of two surfaces that are touching one another. The rougher the two surfaces the higher the friction force. The higher the force pushing the surfaces together the higher the friction force.

10. Newton’s First Law is also known as the Law of Inertia. Inertia is a property of mass. Simply defined, inertia is the resistance of an object to a change in its motion. Which would require more force to move? WHY? The donkey has more __________. mass The > the mass the > the inertia. Therefore, it has more _____________. inertia

11. REVIEW An object at rest will remain at rest and an object in motion will remain in motion at constant speed and in a straight line unless acted on by an outside force. Inertia is the resistance of an object to a change in its motion. The > the mass the > the inertia.

12. The End