- #1

0kelvin

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I have a block with a certain mass attached to a spring. I pull it and then release. Spring pulls block back. When spring is back to its relaxed position, is the velocity of the block positive or negative? Exercise does provide k, mass and x, but that's not where the error is comming from.

According to the law of conservation of energy I have:

$$\frac{1}{2}mv^2 = \frac{1}{2}kx^2$$

I imediately though that since the usual orientation is x is positive to the right and block is moving to the left, velocity should be negative. But there is an example like this in the book and velocity is positive. How so? Absolute value is right, but the sign is wrong.

According to the law of conservation of energy I have:

$$\frac{1}{2}mv^2 = \frac{1}{2}kx^2$$

I imediately though that since the usual orientation is x is positive to the right and block is moving to the left, velocity should be negative. But there is an example like this in the book and velocity is positive. How so? Absolute value is right, but the sign is wrong.

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