1. Newton 1st Law of Motion

2. Review: Forces Net Force Balanced Forces Unbalanced Forces
Combination of all forces acting on a body
Balanced Forces
Body does not accelerate
Remains at rest or constant velocity
Net force = 0 N
Unbalanced Forces
Body accelerates (changes rest or motion)
Net force not equal to 0 N
Acceleration
Occurs only when there are unbalanced forces present

3. SIR ISAAC NEWTON
Described the relationship between force and motion in 3 laws.

4. INERTIA: the tendency of an object…
to resist being moved until an outside force acts on the object.
or if the object is moving:
to resist a change in speed or direction until an outside force acts on the object.
Basically, objects want to keep on doing what they’re doing.

5. INERTIA is related to an object’s MASS. Mass is a measure of inertia.
SI unit for mass is kilograms (kg)
More mass means more inertia.
Objects with smaller masses can be accelerated with smaller forces.
A baseball will accelerate much faster when hit by a bat than a bowling ball hit by the same bat.

6. Which has more inertia?
Tennis ball or
Bowling ball

7. Which has more inertia?
Semi-Truck or
Honda Civic

8. NEWTON’S FIRST LAW OF MOTION:
an object at rest remains at rest unless it experiences an unbalanced force
and
an object in motion maintains its velocity unless it experiences an unbalanced force.
Also called the Law of Inertia

10. Examples
Using ‘inertia’, explain what happens to the dummies in the crash vehicle clip.

11. Examples What is happening when you slip and fall on ice? Friction:
Inertia:
Force:

12. Exit Ticket: #5-8

13. 5. Inertia is the tendency of an object to resist any _______________
5. Inertia is the tendency of an object to resist any _______________. a. speed c. change b. Weight d. all of the above

14. 6. Newton’s 1st Law of Motion states that an object at rest remains at rest and an object in motion maintains it’s ________________ unless it experiences an unbalanced force. a. velocity c. speed b. Direction d. none of the above

15. 7. What is another name for Newton’s 1st Law of Motion. a
7. What is another name for Newton’s 1st Law of Motion? a. Law of Acceleration c. Law of Rest b. Law of Newton d. Law of Inertia

16. 8. Which of the following has the most inertia. a. human hair c
8. Which of the following has the most inertia? a. human hair c. basketball b. Mrs. Bentley d. Mount Everest