How Does Spring Force Affect an Object's Position?

[Ben2002]

1. we must apply a force of magnitude 78 N to hold the block stationary at x = -2.0 cm. From that position we then slowly move the block so that our force does +4.0 J of work on the spring-block system; the block is then again stationary. What is the block's position (x)? (There are two answers.)

2. Fs = -kd (hooke's Law)
Ws=1/2kxi^2 - 1/2kxf^2



3. I am not sure how to use the equations for a spring

 

[ehild]

First find the spring constant from Hook's law.

ehild