Which part of a vibrating string experiences the maximum acceleration?

Which part of a vibrating string experiences the maximum acceleration?
 
  A) nodes
  B) ends
  C) antinodes

Question 2

A solid block of metal is placed in a uniform electric field. Which statement is correct concerning the electric field in the block's interior?
 
  A) The interior field points in a direction opposite to the exterior field.
  B) There is no electric field in the block's interior.
  C) The interior field points in a direction that is parallel to the exterior field.
  D) The interior field points in a direction that is at right angles to the exterior field.

Question 3

Fred swings around a 0.40 kg ball attached to a string at constant speed in an almost horizontal circle of radius 1.3 meters. If one revolution takes 1.4 s:
 
  (a) What is the angular speed of the ball?
  (b) What centripetal force is exerted on the ball?

Question 4

If the phase angle between sound waves from two different point sources is 180, what kind of interference will occur?
 
  A) destructive
  B) constructive
  C) either constructive or destructive

Question 5

Why do power tools with a plastic case not have a 3-prong plug but metal encased tools have (or should have) 3-prong plugs?
 
  What will be an ideal response?

Question 6

The natural frequencies for a stretched string of length L, and wave speed v, are Nv/(2L) where N equals
 
  A) 0, 1, 2, 3, ...
  B) 2, 4, 6, 8, ...
  C) 1, 2, 3, 4, ...
  D) 0, 1, 3, 5, ...
  E) 1, 3, 4, 5, ...