1. Chapter 9 Circular Motion

2. Axis: The straight line about which rotation takes place Rotation: Spin, when an object turns about an internal axis Revolution: when an object turns about an external axis

3. Linear Speed: change in distance/time Tangential Speed (v): the speed of an object moving in a circular path is always tangent to the circle.

4. Rotational Speed or angular speed(  ): number of rotation/ time Tangential speed is directly proportional to the rotational speed and the radial distance from the axis of rotation (r). – What does this mean????

5. Tangential Velocity = (radius)(rotational Speed) As an equation:v = r 

6. Important Equation for a Circle Circumference = 2  r Knowing this, you can solve for – the distance a circular object will move in one rotation – The number of revolutions a circular object will travel in a set distance

7. Frequency (f): Number of times an event occurs in a given unit of time – Units: s -1 or Hertz – Example: 80 beats/60 sec Period (T): The time it takes to complete 1 cycle – Example: 0.75 sec between beats f = 1/T and T = 1/f

8. V = 2  r/T Linear Speed for a given point on a circular path is given by Circumference divided by the period.

9. V = 2  r/T Linear Speed for a given point on a circular path is given by Circumference divided by the period. Example: Identify the linear speed of an object that is 0.1 m from the center of its spin and makes 1 rotation per second.

10. V = 2  r/T Linear Speed for a given point on a circular path is given by Circumference divided by the period. Example: Identify the linear speed of an object that is 0.1 m from the center of its spin and 1 rotation takes 1.5 sec. V = 2  (0.1 m ) / 1.5 sec = 0.42 m/s

11. Centripetal Force: Any force that causes an object to travel in a circular path. The force is directed at a right angle to the path of movement.

12. Centrifugal Force: The outward “force” of circular motion

13. Simulated Gravity Where F = 9.8 m/s 2 You are able to solve for the radius (r) and/or velocity (v) needed for a particular mass to experience the force of gravity!

14. Ch9. part 2, then finish the lab from Ch. 8!