1. Newton’s 1 st & 2 nd Laws Chapter 10 Section 3

2. Newton’s 1 st Law What is an Unbalanced Force? An object will remain at rest OR moving at a constant velocity UNLESS acted upon by an unbalanced force. What is Inertia? Tendency of an object to resist a change in motion…resist speeding up, slowing down, or changing direction

3. Greater Mass = Greater Inertia therefore…Greater the force required to change its motion

4. Let’s Review What happens to passengers when a car stops quickly? What happens to passengers when a car stops quickly? They keep moving until the seatbelt stops them. They keep moving until the seatbelt stops them. How does Newton’s 1 st Law explain what happens to passengers when a car stops quickly? How does Newton’s 1 st Law explain what happens to passengers when a car stops quickly? An object’s motion does not change unless acted upon by an unbalanced force…resistance to change in motion is inertia. The seatbelt exerts the unbalanced force. An object’s motion does not change unless acted upon by an unbalanced force…resistance to change in motion is inertia. The seatbelt exerts the unbalanced force.

5. Is the Force strong enough to move the car?

6. Newton’s 2 nd Law of Motion Acceleration of an object depends on the Net Force acting on the object and the object’s mass. Acceleration = Net Force Mass MassOr Net Force = Mass x Acceleration It is this equation that explains why objects fall at the same acceleration during FREE FALL despite mass.

7. Greater Mass means greater force pulling down… Acceleration = Force/Mass

9. Elephant & Feather fall at SAME rate during Free Fall!!

10. TRUE or FALSE: The elephant and the feather each have the same force of gravity. The elephant and the feather each have the same force of gravity. The elephant has more mass, yet both elephant and feather experience the same force of gravity. The elephant has more mass, yet both elephant and feather experience the same force of gravity. The elephant experiences a greater force of gravity, yet both the elephant and the feather have the same mass. The elephant experiences a greater force of gravity, yet both the elephant and the feather have the same mass. On earth, all objects (whether an elephant or a feather) have the same force of gravity. On earth, all objects (whether an elephant or a feather) have the same force of gravity. The elephant weighs more than the feather, yet they each have the same mass. The elephant weighs more than the feather, yet they each have the same mass. The elephant clearly has more mass than the feather, yet they each weigh the same. The elephant clearly has more mass than the feather, yet they each weigh the same. The elephant clearly has more mass than the feather, yet the amount of gravity (force) is the same for each. The elephant clearly has more mass than the feather, yet the amount of gravity (force) is the same for each. The elephant has the greatest acceleration, yet the amount of gravity is the same for each. The elephant has the greatest acceleration, yet the amount of gravity is the same for each.

11. What about when there is Air Resistance? Wouldn’t the elephant experience more Air Resistance since he has more surface? Try the extra credit to find out…