Two tiny beads, each of mass 3.2 g, carry equal-magnitude ...

[washai]

Two tiny beads, each of mass 3.2 g, carry equal-magnitude charges. When they are placed 6.4 cm apart and released in outer space, they begin to accelerate toward each other at 538 m/s2.
 
  What is the magnitude of the charge on each bead? (k = 1/40 = 9.0  109 N  m2/C2 ) A) 510 nC
  B) 44 nC
  C) 1800 nC
  D) 890 nC
  E) 1300 nC

Question 2

A spaceship traveling at constant velocity passes by Earth and later passes by Mars. In which frame of reference is the amount of time separating these two events the proper time?
 
  A) the Earth frame of reference
  B) the Mars frame of reference
  C) the spaceship frame of reference
  D) any inertial frame of reference
  E) any frame of reference, inertial or not

[ntsoane kedibone]

Answer to Question 1

D

Answer to Question 2

C