The first to be credited for assigning the terms positive and ...

[mynx]

The first to be credited for assigning the terms positive and negative to electricity was
 
  A) William Crookes.
  B) J.J. Thomson.
  C) Robert Millikan.
  D) Benjamin Franklin.
  E) none of the above

Question 2

Three boxes in contact rest side-by-side on a smooth, horizontal floor.
 
  Their masses are 5.0-kg, 3.0-kg, and 2.0-kg, with the 3.0-kg box in the center. A force of 50 N pushes on the 5.0-kg box, which pushes against the other two boxes.
  (a) Draw the free-body diagrams for each of the boxes.
  (b) What magnitude force does the 3.0-kg box exert on the 5.0-kg box?
  (c) What magnitude force does the 3.0-kg box exert on the 2.0-kg box?

[annierak]

Answer to Question 1

Answer: D

Answer to Question 2

(a) The following forces act on the 5.0-kg box: the force due to gravity, normal force, contact force between 5.0-kg mass and 3.0-kg mass, the force of 50 N pushing on the box. The following forces act on the 3.0-kg box: the force due to gravity, normal force, contact force between the 5.0-kg box and the 3.0-kg box, the contact force between the 3.0-kg box and the 2.0-kg box. The following forces act on the 2.0-kg box: the force due to gravity, normal force, contact force between the 3.0-kg box and the 2.0-kg box.
(b) 25 N
(c) 10 N

[mynx]

Gracias!

[hramirez205]

Thanks for the timely response, appreciate it