PHY 107 1st Edition Lecture 12 Outline of Last Lecture I. FrictionOutline of Current LectureII. Drag Force & Terminal SpeedIII. Uniform Circular MotionCurrent LectureDrag Force & Terminal Speed:- Drag – the opposing force an object experiences when moving through a fluid (liquid or gas)o D = ½ CAv2 - C is a constant- A is the effective cross sectional area of the moving object- is the density of the surrounding fluid- v is the object’s speedo Consider an object is moving in air. Initially D = 0, but as the object accelerates, D increases and at a certain speed vt, D = mg. At that point, the net force and the acceleration become zero and the object moves with constant speed vt known as the terminal speed. - ½ CAvt2 = mg → vt = √2 mgC AUniform Circular Motion: - Centripetal force – the direction of the acceleration vector for an object moving on a circular path always points towards the center of rotation C o Magnitude is constant and given by the equation: a = v2r- If Newton’s Law is applied: the net force in the direction that points towards C must havemagnitude: FnetC = mv2r (centripetal force)These notes represent a detailed interpretation of the professor’s lecture. GradeBuddy is best used as a supplement to your own notes, not as a substitute.- “Recipe” for problems involving uniform circular motion: o Draw the force diagram for the objecto Choose one of the coordinate axes to point towards the orbit center Co Determine Fyneto Set Fynet =
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