Does the centripetal force acting on an object do work on the ...

[ts19998]

Does the centripetal force acting on an object do work on the object?
 
  A) no, because the object has constant speed
  B) yes, since it takes energy to turn an object
  C) yes, since a force acts and the object moves, and work is force times distance
  D) no, because the force and the displacement of the object are perpendicular
  E) yes, because the force and the displacement of the object are perpendicular

Question 2

When multiplying several quantities, the number of significant digits in the result must always be
 
  A) larger than the number of significant digits in the most accurate of the quantities.
  B) equal to the number of significant digits in the most accurate of the quantities.
  C) equal to the average number of significant digits in the most and least accurate of the quantities.
  D) equal to the number of significant digits in the least accurate of the quantities.
  E) smaller than the number of significant digits in the least accurate of the quantities.

[kingfahad97]

Answer to Question 1

D

Answer to Question 2

D