How high does a 0.240 kg block rise above a compressed spring?

[hshphyss]

Can anyone help me with this question?

A 0.240 kg block on a vertical spring with a spring constant of 5e3 N/m is pushed downward, compressing the spring 0.080 m. When released, the block leaves the spring and travels upward vertically. How high does it rise above the point of release?

I know that PE= 1/2 kx^2
so I got .5 x 5e3 x .08^2=16 I'm not sure where the mass comes into this equation. I also know that you have to subtract your anser from the point of release so i tried 16-.08 but it didn't work...

Thank-you

 

[whozum]

Is the answer you got (16) a height? What units does it have? What units should it have?

Secondly, if it reaches a maximum height while initially traveling upwards, then something must be pulling it down... what is it? (kinda obvious).

 

[hshphyss]

16 joules is the potential energy
where would you incorporate gravity or weight into the equation??

 

[Doc Al]

Think of this as a conservation of energy problem. Intially, you have spring potential energy, which ends up being transformed into gravitational potential energy. How do you express gravitational PE as a function of height?

 

[kp]

doesn't the block have P.E. as it travels upto to its max height; how would you define the P.E of an object at a certain height?