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# Physics Hooke's law question help watch

1. When a mass of 40 kg is hung from a spring, the spring stretches
by 6 mm. Assuming that Hooke's Law holds good, by how much
more would the spring stretch if an additional mass of 100 kg were
hung from it? What is the spring constant?

Could anyone help solve this plz, Cheer!!
2. Show your working thus far, and people will be happy to point you in the right direction or let you know if you're already on the right track.

You might find it helpful to begin with by writing down Hooke's law, and sketching a typical force-extension graph.
3. (Original post by Tom Downey)
When a mass of 40 kg is hung from a spring, the spring stretches
by 6 mm. Assuming that Hooke's Law holds good, by how much
more would the spring stretch if an additional mass of 100 kg were
hung from it? What is the spring constant?

Could anyone help solve this plz, Cheer!!
(Original post by artful_lounger)
Show your working thus far, and people will be happy to point you in the right direction or let you know if you're already on the right track.

You might find it helpful to begin with by writing down Hooke's law, and sketching a typical force-extension graph.
Im not sure if the answer is right as I haven't used the graph but the equation. Any improvements are verily appreciated!

F= k x
40 kg =392.4 N
e/x = 6 mm= 0.006m

392.4 = k * 0.006

so k = 65400 N/m

after adding 100kg (981N) the new force can be shown through the equation

F = k * x
1373.4 = 65400 * x

x= 0.021m= 21 mm

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