# Spring, block, incline and friction problem, can someone help me (PICTURES inside)

1. Nov 11, 2009

### jjmont17

So we took a quiz in class, no one got it right so now its take home and im lost.
1. The problem statement, all variables and given/known data

2. Relevant equations
.5kxi -Fkd= .5MVf^2
h=dsin(tht)
umgh=fk
fk=ukN

3. The attempt at a solution
I really do not know where to start i tried
(1/2)(500n/m)(12.0)-(3.25)(500n/m)(d)=.5(2)(vf^2)

2. Nov 11, 2009

### ideasrule

Re: spring, block, incline and friction problem, can someone help me (PICTURES inside

Unless the question was meant to say "the block-spring system is initially compressed by 12.0 cm" rather than "the block-spring system is initially compressed to 12.0 cm", this problem is unsolvable. Without knowing the spring's equilibrium length, it's impossible to find how high it travels; if the equilibrium length is 12.1 cm, that's obviously going to give a different result than if it's 54 cm.

If we assume the spring's compressed 12 cm from equilibrium, conservation of energy is the best way to solve this problem. The spring has no kinetic energy at the bottom and none at the top, but it turned elastic potential energy into gravitational potential energy and heat. Express this as an equation, then solve for the distance travelled.