Uniform Circular Motion

I. Core Concepts & Definitions

• Tangential speed: The speed an object has as it travels in a circle; this speed is always tangent to its path and remains constant.

• Centripetal acceleration: The acceleration of an object moving in a circle. How can there be acceleration if the speed is constant? Because the object is constantly changing direction as it follows the path. Velocity is a vector (requiring both magnitude and direction); even though the magnitude (speed) is constant, the changing direction means acceleration is present.

• Centripetal force: Directly tied to Newton's Second Law (F=ma). While force is often used to change an object's speed, in this case, it changes the object's direction. Centripetal force is the net inward force—commonly provided by tension (like in our lab setup), gravity, or friction—that causes the direction of the object to change by constantly pulling it toward the center.

• Period: Time it takes for a body to complete ONE revolution

• Frequency: How many revolutions it can do in a specific unit time REV/S

II. Key Formulas & Derivations

• Vertical String Alignment: Adjust the spring bracket so the string holding the rotating mass hangs completely vertical, aligning with the stationary reference marker.

  
  

• Radius Measurement: Measure the radius precisely from the center of rotation to the center of the mass using the reference pointer.

  
  

• Reference Marker (Orange Indicator): Use the orange indicator as your visual target on every revolution to ensure the mass maintains the correct radius and vertical position while spinning.

  
  

• Apparatus Stability: Ensure the platform and base are securely clamped and level before rotation to prevent wobbling or errors in force distribution.