A thin, circular disk of radius R = 30 cm is oriented in the ...

[daltonest1984]

A thin, circular disk of radius R = 30 cm is oriented in the yz-plane with its center as the origin. The disk carries a total charge Q = +3 C distributed uniformly over its surface.
 
  Calculate the magnitude of the electric field due to the disk at the point x = 15 cm along the x-axis. A)
 
  9.95  105 N/C
  B)
 
  4.98  105 N/C
  C)
 
  3.32  105 N/C
  D)
 
  2.49  105 N/C
  E)
 
  1.99  105 N/C

Question 2

Relative to a stationary observer, a moving object
 
  A)
 
  appears shorter than normal.
  B)
 
  appears longer than normal.
  C)
 
  keeps its same length.
  D)
 
  can do any of the above. It depends on the relative velocity between the observer and the object.
  E)
 
  can do any of the above. It depends on the relative energy between the observer and the object.

[uniquea123]

Answer to Question 1

C

Answer to Question 2

A

[daltonest1984]

Excellent

[scikid]

Gracias!