# Work done by a spring

GreenPrint

## Homework Statement

http://img205.imageshack.us/img205/7536/capturebb.jpg [Broken]

i am stuck on part c

how do i find work with out 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...

Last edited by a moderator:

## Answers and Replies

Homework Helper
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)

Homework Helper
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.