- #1

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F=-k * delta s

52N= -k * 0.73m

52N/0.73N = -k

k= -71.2 N/m or -71 N/m with sig figs.

The negative sign means that the force is opposite of the stretch.

Is this right?

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- Thread starter StephenDoty
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- #1

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F=-k * delta s

52N= -k * 0.73m

52N/0.73N = -k

k= -71.2 N/m or -71 N/m with sig figs.

The negative sign means that the force is opposite of the stretch.

Is this right?

- #2

Dick

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Of course it's right.

- #3

alphysicist

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The force F in Hooke's law is the force of the spring, not the external force that pulls on the spring. Also, F and (delta s) are vectors so we need to keep track of their directions.

So, just to pick a specific direction, let the spring be pulled to the right, and also choose rightwards to be the positive direction. Then (delta s)=+0.73m. But to get the sign of F we need to find which direction the spring is pulling.

- #4

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So:

both the force and the displacement are in the same direction since the sping is being stretched, but the k constant is pulling in the opposite direction so k = 71 N/m pulling the spring in the opposite direction of the stretch.

both the force and the displacement are in the same direction since the sping is being stretched, but the k constant is pulling in the opposite direction so k = 71 N/m pulling the spring in the opposite direction of the stretch.

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- #5

alphysicist

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- #6

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ok..

-52N=-k*0.73m

-52N/0.73m = -k

-71 N/m = -k

71 N/m = k

Which is what I got before.

-52N=-k*0.73m

-52N/0.73m = -k

-71 N/m = -k

71 N/m = k

Which is what I got before.

- #7

alphysicist

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