(adsbygoogle = window.adsbygoogle || []).push({}); 1. The problem statement, all variables and given/known data

a) A 50 g ice cube can slide without friction up and down a 30 degree slope. The ice cube is pressed against a spring at the bottom of the slope, compressing the spring 10 cm. The spring constant is 25 N/m. When the ice cube is released, what total distance will it travel up the slope before reversing direction?

b) The ice cube is replaced by a 50 g plastic cube whose coefficient of kinetic friction is 0.20. How far will the plastic cube travel up the slope?

2. Relevant equations

Us=.5kx^2

U=mgy

change in thermal energy= (force of kinetic friction)*(displacement)

3. The attempt at a solution

I got part a, and I want to make sure I am doing part b correctly.

Here's what I did.

Fk= mgcostheta * coefficient of friction

Fk= (.05kg)(9.80)(cos30)(.20)=.085 N

change in thermal energy= Fk* distance covered up slope (d)

change in thermal energy = .085 * d

I called y the final height so y=dsin30

Kf + Uf + change in thermal energy = Ki + Ui

(.05kg)(9.80)(dsin30) + (.085d) = (.5)(25 N/m)(.1m)^2

d= .379 m = 37.9 cm

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# Homework Help: Am I doing this problem correctly?

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