Section 1-1 Chapter 1

I. Frame of Reference
a. Whenever you describe something that is moving, you are comparing it to something that is assumed to be stationary.

b. The most common frame of reference is the earth.

c. No Frame of reference is more correct than another.

Section 1-2

  1. Measuring motion
  2. A change in position in a certain amount of time is called motion.
  1. Speed
  2. Speed is the rate at which an object moves.
  3. Speed = Distance / Time
  4. Speed is measured in meters or kilometers and seconds or hours (m/sec) or (km/hr).
  5. Constant speed is speed, which never changes. On a graph, constant speed is represented with a straight line.
  6. Average speed is taking total distance divided by total time. Average speed is represented by a changing line on a graph.
  1. Velocity
  2. Velocity is speed in a given direction. Ex: (m/sec East).
  3. If you change direction, speed may remain the same but velocity will change.
  4. Combining velocities is adding the speed of 2 objects moving in the same direction. Ex: boat moving downstream.
  5. If two objects are moving in opposite direction you subtract the 2 speeds.

Section 1-3

I. Changes in Velocity

a. The rate of change in velocity is known as acceleration.

b. If something is accelerating it is speeding up, slowing down(deceleration) or changing direction

c. Acceleration = final velocity-original velocity / Time

d. Acceleration is measured in m/sec/sec or km/hr/hr.

e. Circular motion – objects that move in a circular path are always accelerating even though they are at a constant speed because they are always changing direction.

Section 1-4

  1. Momentum
  2. All moving objects have momentum
  3. The more momentum an object has the harder it is to stop it.
  4. Momentum depends on the mass and the velocity
  5. Momentum= Mass x Velocity
  6. Mass is measured in Kg.
  7. Velocity measured I meters per second
  8. Momentum measured in Kg-m/sec

II.Conservation of momentum

  1. The total momentum of any group of objects remains the same unless an outside force acts upon it.
  2. The momentum lost by one object, is gained by another object. Momentum is always conserved.