3-2 GRAVITY
1. The Law of Gravitation –
1. The Law of Gravitation – Two masses exert an attractive force on each other.
1. The Law of Gravitation – Two masses exert an attractive force on each other. Force depends on the mass of the two objects and the distance between them.
1. The Law of Gravitation – Two masses exert an attractive force on each other. Force depends on the mass of the two objects and the distance between them. If the mass of either of the objects increases, the gravitational force between them increases.
1. The Law of Gravitation – Two masses exert an attractive force on each other. Force depends on the mass of the two objects and the distance between them. If the mass of either of the objects increases, the gravitational force between them increases. If the objects are closer together, the gravitational force between them increases.
2. Four Basic Forces:
2. Four Basic Forces: Gravity
2. Four Basic Forces: Gravity Electromagnetic
2. Four Basic Forces: Gravity Electromagnetic Strong Nuclear
2. Four Basic Forces: Gravity Electromagnetic Strong Nuclear Weak Nuclear
3. Range of Gravity:
3. Range of Gravity: Despite the distance between objects, the gravitational attraction between them never disappears.
3. Range of Gravity: Despite the distance between objects, the gravitational attraction between them never disappears. A gravitational force exists between all matter in the universe.
4. Gravitational attraction of earth causes falling objects to have an acceleration of 9.8 m/s2.
4. Gravitational attraction of earth causes falling objects to have an acceleration of 9.8 m/s2. F=m*a
4. Gravitational attraction of earth causes falling objects to have an acceleration of 9.8 m/s2. F=m*a F=m*9.8m/s2
5. The force of Earth’s gravity is always downward.
5. The force of Earth’s gravity is always downward. Free Fall – when an object is influenced only by the force of gravity.
5. The force of Earth’s gravity is always downward. Free Fall – when an object is influenced only by the force of gravity. All objects fall with the same acceleration no matter how large or small their mass is.
6. Weight – the gravitational force exerted on an object.
6. Weight – the gravitational force exerted on an object. Example: Standing on the floor, earth’s gravitational pull is balanced out by floor exerting an upward force.
7. Gravitational Force (Weight) =
7. Gravitational Force (Weight) = mass * acceleration due to gravity
7. Gravitational Force (Weight) = mass * acceleration due to gravity W = m * 9.8m/s2
7. Gravitational Force = mass * acceleration due to gravity W = m * 9.8m/s2 As one travels away from earth (space), weight decreases because the two objects (person & earth) are further apart.
8. Weight and mass are NOT the same thing.
8. Weight and mass are NOT the same thing. Weight is a force….while…..
8. Weight and mass are NOT the same thing. Weight is a force….while…..mass is a measure of the amount of matter an object contains.
9. Weightlessness –
9. Weightlessness – free from the effects of gravity
10. Projectiles -
10. Projectiles - Projectile – anything that is thrown or shot through the air.
10. Projectiles - Projectile – anything that is thrown or shot through the air. Travel in a curved path
10. Projectiles - Projectile – anything that is thrown or shot through the air. Travel in a curved path Horizontal velocity (forward) from the “thrower” and a vertical velocity (downward) from gravity
11. Centripetal Acceleration –
11. Centripetal Acceleration – acceleration (ie change in speed, direction, or both) toward the center of a curved or circular path.
12. Centripetal Force –
12. Centripetal Force – force directed toward the center of the circle for an object moving in a circular motion.