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**1. Problem**

In the figure, we must apply a force of magnitude 63 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 +4.1 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.)

Here's the figure: http://www.webassign.net/hrw/7-11a.gif

? cm (smaller value)

? cm (larger value)

**2. Attempt at a solution**

+4.1 J = (1/2)k * (x

_{f}

^{2}- x

_{i}

^{2})

(+63 N)î = -k(-2.0 cm)î k = 3.15 x 10

^{3}N/M

x

_{i}= -2.0 cm

I got some weird decimal answer which was apparently wrong.

I also don't understand what the smaller and larger value is.

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