BR physics chapter 5 question

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sbuxaddict

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Example 5.2b from BR has me a little confused.

Q: When a vertically oriented sprig scale supports a 180-N block, the spring stretches 0.3m from rest. Neglecting any other masses associated with the scale, what is the value of the spring constant?

I get how to set it up, I calculated it it as:
mg = -kx
k = mg/x
k = ((180)(10))/0.3
k = 1800/0.3 = 6000

The answer in the book has this:
mg = -kx
k = mg/x
k = 180/0.3 = 600

Am I missing something, or was there a possible typo?
 
Example 5.2b from BR has me a little confused.

Q: When a vertically oriented sprig scale supports a 180-N block, the spring stretches 0.3m from rest. Neglecting any other masses associated with the scale, what is the value of the spring constant?

I get how to set it up, I calculated it it as:
mg = -kx
k = mg/x
k = ((180)(10))/0.3
k = 1800/0.3 = 6000

The answer in the book has this:
mg = -kx
k = mg/x
k = 180/0.3 = 600

Am I missing something, or was there a possible typo?

You didn't need to multiply by 10 because 180 N is the weight, not the mass.
mg = 180N
 
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