1. Laws of Motion Forces: chapter 11

2. 1 st Law An object at rest remains at rest and an object in motion maintains its velocity unless it experiences an unbalanced force.

3. 2 nd Law The unbalanced force acting on an object equals the object’s mass times its acceleration: force = mass x acceleration F = ma

4. Calculate the force of… A block of ice with a mass of 12.5 kg being accelerated at a rate of 3.5 m/s 2

5. 2 nd Law continued… Or, the acceleration of an object is proportional to the net force on the object and inversely proportional to the object’s mass: acceleration = force ÷ mass a = F ÷ m

6. Calculate the rate of acceleration... of a sailboat with a mass of 655 kg while it experiences a net force of 895 N

7. Law of Universal Gravitation Newton generalized his observations on gravity in a law now known as the law of universal gravitation. Mathematically, the law of universal gravitation is stated as: F = G (m 1 m 2 ÷ d 2 )

8. Math Skills The force between a planet and a spacecraft is 1 million newtons. What will the force be if the spacecraft moves to half its original distance from the planet?

9. Free Fall and Weight The free-fall acceleration of an object due to gravity near the Earth’s surface is 9.8m/s2 Weight is equal to mass times free-fall acceleration w = mg

10. Calculate the weight of… A 65 kg astronaut on the surface of the moon, where g = 1.6 m/s 2

11. 3 rd Law For every action force, there is an equal and opposite reaction force.

12. Momentum Moving objects have momentum. Momentum is a quantity defined as the product of the mass and velocity of an object.

13. Momentum Equation Momentum = mass x velocity p = mv

14. Calculate the momentum of… a 65 kg skateboarder moving forward at the rate of 3.0 m/s