Why is it so difficult to remove the lid from a vacuum-sealed ...

[michelleunicorn]

Why is it so difficult to remove the lid from a vacuum-sealed jar?
 
  A) The air pressure outside the jar pushes downward on the lid more strongly than the air pressure inside pushes upward on the lid.
  B) The higher pressure inside the jar pulls inward on the lid, holding it firmly to the jar.
  C) The vacuum inside the jar pulls inward on the lid, holding it firmly to the jar.
  D) The vacuum inside the jar pushes outward on the lid, holding it firmly to the jar.
  E) The air pressure inside the jar pushes upward on the lid more strongly than the air pressure outside pushes downward on the lid.

Question 2

Of the four fundamental forces that act in the universe, which one supports a book that is at rest on a table?
 
  A) the photon force
  B) the gravitational force
  C) the electromagnetic force
  D) the strong nuclear force
  E) the perpendicular force

[blakcmamba]

Answer to Question 1

A

Answer to Question 2

C

[michelleunicorn]

Wow, this really help

[atrochim]

Gracias!