Find max compression of spring, block on incline

[DrWillVKN]

Homework Statement

A 5 kg block is placed near the top of a frictionless ramp, which makes an angle of 30o degrees to the horizontal. A distance d = 1.3 m away from the block is an unstretched spring with k = 3000 N/m. The block slides down the ramp and compresses the spring. Find the maximum compression of the spring.

Homework Equations

mgh = PEgravitational
(0.5)kx^2 = PEspring

The Attempt at a Solution

Since energy is conserved, i set them equal to one another, with h = sin(30)*1.3. x gives 0.146m as maximum compression. Webassign doesn't take this as the right answer. I tried all numbers from 0.01 - 1.99, none are the right answers. This question is making me want to smash my computer. (Also, I tried negative values too.)

 

[rock.freak667]

Your method and your answer is correct. Does Webassign ask for it in cm or another unit?

 

[DrWillVKN]

Your method and your answer is correct. Does Webassign ask for it in cm or another unit?

It's in meters. If the answer is correct, I'd check with the instructor, thanks.

 

[SammyS]

If the spring is compressed by an amount x, then h is given by:

h=(1.3+x)\sin(30^{\circ})\,.

The block moves more than 1.3m down the incline.

 

[DrWillVKN]

If the spring is compressed by an amount x, then h is given by:

h=(1.3+x)\sin(30^{\circ})\,.

The block moves more than 1.3m down the incline.

oh wow, that makes sense now, thanks!