What is the velocity of the object after it has been displaced by the spring?

[GreenPrint]

Homework Statement

http://img205.imageshack.us/img205/7536/capturebb.jpg

i am stuck on part c

how do i find work without using the spring constant

Homework Equations

work equals force parallel times displacement at which the force is acted during...

Work done by spring = .5 kx^2
Work = delta K

but delta K = 0 because the table top is frictionless

Work = delta U
delta U = 0 in this situation correct?

The Attempt at a Solution

so I'm stuck...

i think it might be zero but .5 kx^2 would not give zero now would it...

 

[rl.bhat]

The work done on the block by the spring is equal to the change in KE of the block.

 

[GreenPrint]

hmmmmmmmm... so then... um...

 

[GreenPrint]

ok thanks

 

[GreenPrint]

wait so to find the spring constant...

is delta U = delta K = W = .5 kx^2

?

 

[GreenPrint]

- (Mg)/(2h)

 

[rl.bhat]

wait so to find the spring constant...

is delta U = delta K = W = .5 kx^2

?

0.5 kx^2 = 0.5 Mv^2.
From the given data you can find v.