Solving a Several Step Problem: Velocity & Thermal Energy

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Homework Help Overview

The discussion revolves around a physics problem involving a block sliding along a track with varying conditions, including friction and spring compression. The problem is set in the context of energy conservation, specifically focusing on potential and kinetic energy, as well as thermal energy due to friction.

Discussion Character

  • Exploratory, Conceptual clarification, Mathematical reasoning

Approaches and Questions Raised

  • Participants explore the conservation of energy principles to relate potential and kinetic energy. There are discussions on the effects of friction on the block's motion and how to calculate the resulting thermal energy. Some participants question the setup and the necessary equations for each part of the problem.

Discussion Status

Some participants have provided calculations for parts of the problem, including potential and kinetic energy, and have shared their reasoning regarding the effects of friction. There is ongoing exploration of how to approach the final part of the problem concerning the spring constant.

Contextual Notes

Participants note the initial conditions, such as the mass of the block and the dimensions of the track, as well as the coefficient of kinetic friction. There is an acknowledgment of the need for clarity on how to transition from one part of the problem to the next, particularly regarding the relationship between energy and the spring's properties.

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Homework Statement



Consider the track shown in the figure. The section AB is one quadrant of a circle of radius r = 2.0 m and is frictionless. B to C is a horizontal span 3.3 m long with a coefficient of kinetic friction µk = 0.25. The section CD under the spring is frictionless. A block of mass 1 kg is released from rest at A. After sliding on the track, it compresses the spring by 0.20 m.

a)Determine the velocity of the block at point B.
b)Determine the thermal energy produced as the block slides from B to C.
c)Determine the velocity of the block at point C.
d)Determine the stiffness constant k for the spring.

Homework Equations



http://www.webassign.net/gianpse3/8-32alt.gif

The Attempt at a Solution


I am not sure how to begin. I know the conservation of energy equation comes into play...
 
Last edited:
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At first, there is only potential energy. Once at the bottom, it has all turned to kinetic energy. These energies will be equal.

Potential = 9.8*Mass*Height
Kinetic = 1/2*Mass*Velocity2

This allows you to solve for velocity. Once on the track, it will experience a deceleration due to friction, with no other horizontal forces acting on it, seemingly. Friction force = normal force*coeff of friction. Turn the friction force into an acceleration and use kinematics to find it's final velocity. At the spring, use the velocity to find it's kinetic energy again. Energy and work interchange, and the work to compress a spring is 1/2*Spring constant*Compression distance2

What is the ultimate question?
 
Consider the track shown in the figure. The section AB is one quadrant of a circle of radius r = 2.0 m and is frictionless. B to C is a horizontal span 3.3 m long with a coefficient of kinetic friction µk = 0.25. The section CD under the spring is frictionless. A block of mass 1 kg is released from rest at A. After sliding on the track, it compresses the spring by 0.20 m.

a)Determine the velocity of the block at point B.
b)Determine the thermal energy produced as the block slides from B to C.
c)Determine the velocity of the block at point C.
d)Determine the stiffness constant k for the spring.

Sorry, I forgot the actual questions in the first post.
 
Last edited:
I have been trying to solve this all night and have gotten this far:

a) V=square root of 2(9.8m/s^2)(2m) V=6.26m/s
b) (.25)(9.8m/s^2)(3.3m)(1kg)=8.09 J
c) 1/2(1kg)V^2-1/2(1kg)6.25m/s)=0 V=2.50m/s
Are these correct? How do I do part d. I know part d involves 1/2(-k)x, but I am not sure what information is important form parts a, b, and c.
 
Last edited:
It worked out, thanks for the pointers ;)
 

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