Am I doing this problem correctly?

  • Thread starter bcjochim07
  • Start date
  • #1
374
0

Homework Statement



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?


Homework Equations


Us=.5kx^2
U=mgy
change in thermal energy= (force of kinetic friction)*(displacement)


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
 

Answers and Replies

  • #2
jamesrc
Science Advisor
Gold Member
476
1
Looks good.
 

Related Threads on Am I doing this problem correctly?

Replies
1
Views
762
  • Last Post
Replies
5
Views
1K
Replies
6
Views
2K
  • Last Post
Replies
7
Views
2K
Replies
4
Views
1K
  • Last Post
Replies
20
Views
2K
Replies
5
Views
441
Replies
0
Views
9K
Replies
7
Views
6K
Replies
3
Views
553
Top