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What is the largest mass that can be placed on the spring

  • Thread starter jaron
  • Start date
  • #1
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Homework Statement


the spring in a typical hooke's law apparatus has a force constant of 1.50 N/m and a maximum extension of 10cm. what is the largest mass that can be placed on the spring without damaging it?


Homework Equations


what i believe to be relevant:
F=-kx
W=F"d
E=mg(h)


The Attempt at a Solution


F=1.5(0.10)
F=0.15

W=F"d
W=0.15(0.10)
W=0.015J

0.015=m(9.81)(0.10)
0.015/0.981=m
m=0.0153kg <----------- answer

now i have no idea how this can be wrong.. i have gone over it many times now.
my textbook has it as 0.153kg.
am i right on this one?
 

Answers and Replies

  • #2
172
1


Homework Statement


the spring in a typical hooke's law apparatus has a force constant of 1.50 N/m and a maximum extension of 10cm. what is the largest mass that can be placed on the spring without damaging it?


Homework Equations


what i believe to be relevant:
F=-kx
W=F"d
E=mg(h)


The Attempt at a Solution


F=1.5(0.10)
F=0.15

W=F"d
W=0.15(0.10)
W=0.015J

0.015=m(9.81)(0.10)
0.015/0.981=m
m=0.0153kg <----------- answer

now i have no idea how this can be wrong.. i have gone over it many times now.
my textbook has it as 0.153kg.
am i right on this one?
I was able to solve this by using a force analysis. You don't need to even use energy.

Try finding what mass puts the system in static equilibrium at the spring's maximum extension and solve for mass.

There might be a way to solve it with the energy equations, but I don't really see a need to go that route. The only thing I can see is if you go that direction, the force exerted by the spring isn't constant, it's a function of x. But like I said, you don't even need to go that route.

Draw a free body diagram and the answer should be obvious.
 

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