What is the solution to a block sliding on an incline connected to a spring?

[matt62010]

shm/spring question, please help!

Homework Statement

A block weighing 16.0 N is able to slide without friction on a 37.0° incline. It is connected to the top of the incline by a massless spring of unstretched length 0.550 m and spring constant 180 N/m.
(a) How far down the incline would you have to place the block so it would not oscillate when you let go?

(b) If the block is pulled slightly down the incline from where you placed in part (a) and released, what is the period of the resulting oscillations?

Homework Equations

The Attempt at a Solution

I have no idea how to even start this problem. Any help is greatly appreciated!

 

[glueball8]

for a) try mgh=1/2*k*x^2

 

[glueball8]

for b) try using simple harmonic motion

http://en.wikipedia.org/wiki/Simple_harmonic_motion

 

[matt62010]

don't i need to take into account the angle for part a?

 

[glueball8]

yes but that's just trig

 

[matt62010]

i'm not sure what you mean

 

[badreligion]

For a) you will want to force of the spring to equal the force of gravity on the block acting at that angle.

 

[matt62010]

thanks for your help guys!

 

[soccer_09]

Can someone please explain to me what I'm doing wrong with this problem?

In Fig. 16-35, a block weighing 17.0 N is able to slide without friction on a 32.0° incline. It is connected to the top of the incline by a massless spring of unstretched length 0.475 m and spring constant 110 N/m.

Those are my numbers... I got part B.

I noticed the part where someone said that the force of the spring = Force of gravity. I saw another problem and plugged the numbers in and got the right answer.

The force of spring = kx and
The force of grav = mg cos(theta)

By doing this my answer should be x = [ mg cos (theta) ] / k
which comes out to be about 1.284

This showed up as incorrect. Some guidance about what I'm doing wrong is greatly appreciated.