In the figure, we must apply a force of magnitude 81.0 N to hold the block stationary at x = -3.00 cm. From that position, we then slowly move the block so that our force does +5.00 J of work on the spring-block system; the block is then again stationary. What are the block's positions? ((a) positive and (b) negative) *=0 Block F,= 0 attached 20902000 to spring - X * positive d F. negative F (a) x negative F, positive -X (b) (a) Number H 6.7 Units cm (b) Number H -6.7 Units cm