Conceptual Dynamics - Independent Learning

Plane Curvilinear Motion - Constrained & Dependent Motion

 

Ropes & pulleys

 

Watch the following video

 

Eureka! The Pulley

 

Lecture content

 

Watch the animation and answer the questions posed.

 

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Solving rope & pulley problems

 

Lecture content

 

Step 1: Choose a datum(s)
  • A datum line is fixed.
  • Used as an origin to measure distances.
  • One datum for every direction of motion.

 

Step 2: Position coordinates
  • Measure the distances from the datum to each moving particle.

 

Step 3: Rope lengths
  • Write down the length of each rope in terms of the position coordinates.
  • The number of ropes = degrees of freedom

 

Step 4: Time derivatives
  • Take the time derivative of the length equation to obtain the velocity and acceleration equations.

 

Step 5: Solve and verify
  • Solve the problem and make sure that the answers make sense in terms of the signs and magnitudes.