Science

• FREE-BODY DIAGRAM

  is a diagram showing all the known and unknown forces acting on the object indicating their magnitude and direction
• Assumptions in FBD

  1.Pulleys are assumed frictionless

  2.Pulleys are assumed weightless

  3.Ropes, cables, ropes, cord, and wires are assumed weightless
• KINDS OF FRICTION

  • kinetic friction
  • static friction
• Static friction

  -is the force of friction present on an object that is about to move.
• Kinetic Friction

  -is the force of friction that is present on an object that is moving
• TWO FACTORS that affect FRICTION

  1.The nature of material

  2.The degree to which the materials are pressed together (Normal Force)
• Axis- Objects tend to rotate on an imaginary straight line in the middle
• ROTATION - when an object turns about an internal axis
• REVOLUTION - when an object turns about an external axis
• frequency - the number of complete rotation or revolution per unit time.
• Formula of frequency $f =$$1/T$
• unit of frequency

  rad/s or Hz
• speed- distance traveled in a given time interval.
• Types of speed

  • Angular speed
  • Tangular speed
• Angular Speed or Rotational Speed

  -Refers to the number of times an object rotates or revolves per unit of time.
• Gravity - is a force which is present everywhere. It pulls everything with mass or energy toward one another.
• The acceleration directed toward the center is specifically named centripetal acceleration (ac)
• uniform circular motion- the magnitude of velocity or speed remains the same, while the direction keeps changing as the object moves around the circie.
• Formula of Centripetal force $Fc=$$mv^2/r$
• Formula of Centripetal acceleration $v^2/r$
• Formula of Frictional force $Ff=$$Fμ Fnorm$
• unit of radius

  • m
• Formula of circular acceleration $ac =$$v^2r$