Machine-translated by Google. Questions are authored in English.
Top

Discussion

Inertia force on a vibrating mass acts

  • A.opposite to the direction of its acceleration
  • B.in the same direction as its acceleration at every instant
  • C.at right angles to the direction of motion of the mass
  • D.always vertically downwards regardless of the motion

Answer: A

Correct answer: opposite to the direction of its acceleration

The inertia force is \( -m\ddot{u} \), so it opposes the acceleration - the mass's resistance to being accelerated, written as though it were a force.

That sign is what makes D'Alembert's principle work: adding the inertia force to the real forces produces a set that sums to zero, so the dynamic problem can be handled with the methods of statics. Its direction has nothing to do with gravity, which enters separately as a static load.

No comment is present. Be the first to comment.
Loading…

Post your comment

Please log in or register to post a comment.