Newton 1st Law of Motion

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

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

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.

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.

Which has more inertia? Tennis ball or Bowling ball

Which has more inertia? Semi-Truck or Honda Civic

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

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

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

Exit Ticket: #5-8

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

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

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

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