Coursera 3

The Lagrangian for a mechanical system is

• the kinetic energy plus the potential energy.

  
  

• the kinetic energy minus the potential energy.

  
  

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Which of the following could be a centripetal term in the dynamics?

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Which of the following could be a Coriolis term in the dynamics?

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Which of these is a possible mass matrix M(θ) for a two-joint robot at a particular configuration θ? Select all that apply.

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True or false? If you grab the end-effector of a robot and try to move it around by hand, the apparent mass (to you) depends on the configuration of the robot.

• True

• False

True or false? If you apply (by hand) a linear force to the end-effector of a robot, the end-effector will accelerate in the same direction as the applied force.

• Sometimes true, sometimes false.

  
  

• Always true

• Always false

How is the center of mass of a rigid body defined?

• The point at the geometric centroid of the body.

• The point at the mass-weighted (or density-weighted) centroid of the body.