1. Matter & Motion

2. Isaac Newton
1643 – 1727
Newton, age 46
Newton, age 82

3. Motion – Terms & Definitions
Speed = rate of change of position
e.g., miles/hour, meters/second
Velocity = speed in a specific direction
e.g., 20 meters/sec, north
20 kilometers/sec, up
Acceleration = rate of change of velocity
* requires change in speed and/or direction

4.  Auto goes from 0 to 90 mph in 7 sec: accelerated motion
Auto rounds curve at constant
40 mph: accelerated motion

5. Catch a baseball – ball stops:
accelerated motion

6. Laws of Motion
1. In the absence of a net force, an object moves with constant velocity.
* Force = “push or pull”

7. Laws of Motion
In the absence of a net force, an objects tend to maintain constant velocity. 2.
For every action force, there exists an equal and opposite reaction force:
action = reaction

8. If gravity exceeds air resistance, then person accelerates.
Falling through
the
atmosphere . . .
Net force is combination of
air resistance and gravity.
air resistance
If gravity exceeds air resistance,
then person accelerates.
gravity

9. Catching a ball again:
FH  Force on hand due to ball
FB  Force on ball due to hand
FH = FB FH FB

10. Rocket Propulsion . . . Rocket pushes on exhaust;
exhaust pushes on rocket.
Forces are equal!
Yeah!