A 10-kilogram block is pushed across a horizontal surface with a ...

[ssal]

A 10-kilogram block is pushed across a horizontal surface with a horizontal force of 20 N against a friction force of 10 N. The acceleration of the block is
 
  A) 1 m/s2.
  B) 2 m/s2.
  C) 5 m/s2.
  D) 10 m/s2.
  E) none of the above

Question 2

A 10-kilogram block with an initial velocity of 10 m/s slides 10 meters across a horizontal surface and comes to rest. It takes the block 2 seconds to stop. The stopping force acting on the block is about
 
  A) 5 N.
  B) 10 N.
  C) 25 N.
  D) 50 N.
  E) none of the above

[Brummell1998]

Answer to Question 1

Answer: A

Answer to Question 2

Answer: D