SPS8.c Relate falling objects to gravitational force.

1

• SPS8.c Relate falling objects to gravitational
  force.

2

• SPS8.d Explain the difference in mass and weight.

3

• EQ How do weight and mass differ with respect to
  gravitational force?

4
Weight and Mass

• How are weight and mass related?

5
12-2-1 Weight and Mass

• weight a measure of the gravitational force
  exerted on an object

6
12-2-2 Weight and Mass

• Weight is equal to mass times free-fall
  acceleration.

7
12-2-3 Weight and Mass

• weight mass x free-fall acceleration, or w mg

8
12-2-4 Weight and Mass, continued

• Weight like force is measured in newtons.

9
12-2-5 Weight and Mass, continued

• mass a measure of the amount of matter in an
  object

10
12-2-6 Weight and Mass, continued

• weight the gravitational force an object
  experiences because of its mass

11
Law of Universal Gravitation

• Why do objects fall to the ground when dropped?

12
12-2-7 Law of Universal Gravitation

• All objects in the universe attract each other
  through the force of gravity.

13
12-2-8 Law of Universal Gravitation, continued

• Newtons law of universal gravitation gives the
  size of the gravitational force between two
  objects

14
12-2-9 Law of Universal Gravitation, continued

• m1 and m2 are the masses of the two objects
• d is the distance between the two objects
• G is a constant

15
12-2-10 Law of Universal Gravitation, continued

• All masses have gravitational attraction for
  other masses no matter how small or large the
  mass is.

16
12-2-11 Law of Universal Gravitation, continued

• Gravitational force increases as mass increases
  and
• decreases as distance increases.

17
Law of Universal Gravitation, continued
18
12-2-12 Free Fall

• In the absence of air resistance, all objects
  falling near Earths surface accelerate at the
  same rate regardless of their mass.

19
12-2-13 Free Fall

• free fall the motion of a body when only the
  force of gravity is acting on the body

20
12-2-14 Free Fall, continued

• Air resistance can balance weight.

21
12-2-15 Free Fall, continued

• terminal velocity the constant velocity of a
  falling object when the force of air resistance
  is equal in magnitude and opposite in direction
  to the force of gravity

22
Projectile Motion

• Why does a projectile follow a curved path?

23
12-2-16 Projectile Motion

• Projectile motion has two componentshorizontal
  and vertical, which combine to form a curved
  path.

24
12-2-17 Projectile Motion

• projectile motion the curved path that an object
  follows when thrown, launched, or otherwise
  projected near the surface of Earth

25
12-2-18 Projectile Motion, continued

• After you have thrown a ball, no horizontal
  forces are acting on the ball (if air resistance
  is ignored). So, the horizontal component of
  velocity of the ball is constant after the ball
  leaves your hand.

26
12-2-19 Projectile Motion, continued

• When you throw a ball, gravity pulls it downward,
  which gives the ball vertical motion. In the
  absence of air resistance, gravity on Earth pulls
  objects that are in projectile motion downward
  with an acceleration of 9.8 m/s2, just as it
  pulls down all falling objects.

27
Projectile Motion, continued

• Orbiting is projectile motion.