1. Ch. 3 Forces 3.1 Newton’s Second Law 3.2 Gravity 3.3 The Third Law of Motion

2. Newton’s Second Law Increase Force=Increase AccelerationIncrease Force=Increase Acceleration Increase Mass=Increase ForceIncrease Mass=Increase Force F= ma F= ma A one-eyed kitty is being pulled by a car at an acceleration of 2.0 m/s 2. What is the mass of the kitty cat if the net force on the kitty is 1000 N?A one-eyed kitty is being pulled by a car at an acceleration of 2.0 m/s 2. What is the mass of the kitty cat if the net force on the kitty is 1000 N?

3. Friction Inertia-in motion, stays in motion? Impossible- Friction (air resistance). Opposing motion of an object.Inertia-in motion, stays in motion? Impossible- Friction (air resistance). Opposing motion of an object.

4. Terminal Velocity: –Downward force – Gravity –Upward force- Air resistance BALANCE OUT- Net Force= 0BALANCE OUT- Net Force= 0 NO more accelerationNO more acceleration

5. 3.2 Gravity Attractive force b/t two objectsAttractive force b/t two objects Depends on MASS and DISTANCEDepends on MASS and DISTANCE The Law of Universal Gravitation –Gravity b/t two objects decrease as the distance increases. Force of Earth’s Gravity F=mg Weight Equation W=mg W=mg

6. Calculations 1.On Earth, what is the weight of a killer whale that has a mass of 200 kg? 2.Find the acceleration of gravity on Uranus, if a person has a mass of 60 kg, and a weight of 200 N. 3.Find the force exerted by a rope on a 10 kg. Mass that is hanging from the rope?

7. Projectile Motion Horizontal and Vertical MotionHorizontal and Vertical Motion

8. Centripetal Force Acceleration toward the center of a circular path.Acceleration toward the center of a circular path.

9. 3.3 The Third Law of Motion To every action there is an equal and opposite reaction. Momentum Equation Momentum Equation p=mv p=mv -Amount of force to -Amount of force to change is motion change is motion

10. Calculations 1. What is the momentum of a really fast and fat cheetah with a mass of 1,000 kg traveling at a speed of 28 m/s? 2. A baseball has a momentum of 6.0 kg m/s. If the mass of the baseball is 0.15 kg. What is the speed of the baseball? 3. What is the mass of a donkey walking at a speed of 1.0 m/s if the donkey’s momentum is 50 kg m/s?

11. Homework Pg 834 #25-37