1. Activator Write the questions and your answers: What is your definition of weight? What is your definition of mass?

2. Gravity Definition A force of attraction between all objects with mass. All objects fall at approximately 10 m/s 2.

3. Gravity Example Gravitational force hold us down. Gravity causes objects to fall toward earth.

4. Weight Definition The force of gravity acting on an object. Weight = mass x acceleration due to gravity w = m x g

5. Weight Example An object with a mass of 10 kg has a weight of 100 N. w = m × g w = 10 kg x 10 m/s 2 w = 100 N

6. Mass Definition The amount of matter (stuff) in an object. Measured on a triple beam balance.

7. Mass Example Units of measure equal grams ( g ) or kilograms ( kg )

9. Video Quiz 1.Define gravity. 2.What is the difference between mass and weight? 3.Why do the feather and hammer hit the ground at the same time? 4.How does weightlessness affect astronauts? 5.Why do the planets orbit the Sun?

10. Activator In your own words, describe the difference between weight, mass, and gravity.

11. Weight, Mass and Gravity w = m × g w – Weight (Newtons) m – Mass (kg) g – acceleration due to gravity (10 m/s 2 )

12. An astronaut has a mass of 75 kg. What is their weight? Q:Ra: I:C: F:

13. A toy car has a weight of 2.6 N. What is the mass of the toy car? Q:Ra: I:C: F:

14. Find the mass of a 40 N object on Earth. Q:Ra: I:C: F:

15. Find the weight of a 30 kg object on Earth. Q:Ra: I:C: F:

16. A ball has a mass of 1 kg. Find its weight. Q:Ra: I:C: F:

17. A bag of groceries has a weight of 44 N. Find its approximate mass. Q:Ra: I:C: F:

18. A marble has a mass of 0.002 kg. Find its approximate weight. Q:Ra: I:C: F:

19. Activator What is the mass of an object that has a weight of 750 N on Earth where the acceleration due to gravity is 10 m/s 2 ? QFC IRa