Elastic Gravitational Potential ENergy

[salman213]

1. A spring is suspended froma ceiling and a 256 g mass is attached to it and pulled down to stretch the spring by 18.2 cm. THe mass is released and travels through the equilibrium position with a speed of 0.746 m/s. Calculate the force constant of the spring/



2. 1/2kx^2 = Ee
1/2mv^2 = Ek
Eg = mgh



3. (DeltaEk - DeltaEg) = DeltaEe
I made my reference point where the spring is stretched until so i guess it has a heigh of 18.2 cm
1/2(0.256)(0.746)^2 - (0.256)(9.81)(0.182) = 1/2k(0.182^2)

and i solve for k

I have another post alread so if u have not read that what then ill tell u here that i have an exam comming up in a few days so i was reviewing my old review problems/tests/ and i found this question on my older test that i screwed up..but he never went through how to do it so i d k how to do it lol

thanks for anyones help in advance:)
This quest

 

[salman213]

any help pleaseeeeeee

 

[Dick]

You have the right concept but you want DeltaEe-DeltaEg=DeltaEk. Potential energy of spring-gravitational potential energy=kinetic energy.

 

[salman213]

ahhh that makes sense cool..

so since the energy of the spring is being converted to kinetic energy but some of the spring energy is being reduced due to gravitational energy not all of it gets transferred to kinetic..right?
so basically

1/2(0.256)(0.746)^2 = 1/2k(0.182^2) - (0.256)(9.81)(0.182)

and hten i solve for k..

 

[Dick]

ahhh that makes sense cool..

so since the energy of the spring is being converted to kinetic energy but some of the spring energy is being reduced due to gravitational energy not all of it gets transferred to kinetic..right?
so basically

1/2(0.256)(0.746)^2 = 1/2k(0.182^2) - (0.256)(9.81)(0.182)

and hten i solve for k..

Exactly correct.