A 10-kg object, hung by an ideal spring, causes the spring to ...

[jake]

A 10-kg object, hung by an ideal spring, causes the spring to stretch 2.0 cm. What is the spring constant for this spring?
 
  A) 5.0 N/cm
  B) 49 N/cm
  C) 0.20 N/cm
  D) 20 N/m
  E) 0.0020 N/cm

Question 2

Velma is in a train headed north past Mort at 30 m/s. Velma has a slingshot that can shoot pebbles at 40 m/s. Velma shoots a pebble toward the rear of the train. Mort observes the pebble's velocity to be
 
  A) 70 m/s north.
  B) 70 m/s south.
  C) 40 m/s south.
  D) 10 m/s south.
  E) 10 m/s north.

[rleezy04]

Answer to Question 1

B

Answer to Question 2

D