Insights Blog
-- Browse All Articles --
Physics Articles
Physics Tutorials
Physics Guides
Physics FAQ
Math Articles
Math Tutorials
Math Guides
Math FAQ
Education Articles
Education Guides
Bio/Chem Articles
Technology Guides
Computer Science Tutorials
Forums
Intro Physics Homework Help
Advanced Physics Homework Help
Precalculus Homework Help
Calculus Homework Help
Bio/Chem Homework Help
Engineering Homework Help
Trending
Featured Threads
Log in
Register
What's new
Search
Search
Search titles only
By:
Intro Physics Homework Help
Advanced Physics Homework Help
Precalculus Homework Help
Calculus Homework Help
Bio/Chem Homework Help
Engineering Homework Help
Menu
Log in
Register
Navigation
More options
Contact us
Close Menu
JavaScript is disabled. For a better experience, please enable JavaScript in your browser before proceeding.
You are using an out of date browser. It may not display this or other websites correctly.
You should upgrade or use an
alternative browser
.
Forums
Homework Help
Introductory Physics Homework Help
Change in temperature after an inelastic collision
Reply to thread
Message
[QUOTE="powerof, post: 4776279, member: 357524"] [h2]Homework Statement [/h2] We have a sphere of mass M=0.75 Kg hung from the ceiling by a massless tense cord. Said sphere is hit by a projectile/bullet of mass m=0.015 Kg with velocity [itex]v_{0}=300 m/s[/itex] and they are stuck together (inelastic collision). Find the height the (projectile+sphere) object reaches and whether it will get heated (ie, is there any heat produced by the impact). If so, calculate the change in the temperature of the object. The bullet and the sphere both have the same temperature at the moment of impact. Known data: [B]M[/B], [B]m[/B], [itex]v_{0}[/itex] and the specific heat capacities: [B]c(sphere)[/B]: 0.03 cal/(g ºC), [B]c(bullet)[/B]: 0.12 cal/(g ºC). [h2]Homework Equations[/h2] Q=mcΔT, p=mv, KE=.5mv^2, PE ≈ mgh, ME=KE+PE [h2]The Attempt at a Solution[/h2] Concerning the height, it is relatively easy to solve. The net force on the system is (assumed to be) zero, therefore the lineal momentum is conserved: [itex]mv_{0}+M \cdot 0=(m+M)v_{f}\Rightarrow v_{f}=\frac{mv_{0}}{(m+M)}[/itex] From the moment of collision onwards the mechanical energy is conserved since only conservative forces (gravity) affect the system. Also at the highest point the kinetic energy is null (for the potential energy I take as a reference point h=0 the initial level/height of the bullet and sphere): [itex]\frac{1}{2}(m+M)v_{f}^{2}+mg \cdot 0=\frac{1}{2}(m+M) \cdot 0+(m+M)gh \Rightarrow v_{f}^{2}=2gh \Rightarrow (\frac{mv_{0}}{(m+M)})^2=2gh\Rightarrow h= \frac{1}{2g}(\frac{mv_{0}}{(m+M)})^2[/itex] (note that [itex]v_{f}[/itex] is actually the initial velocity but I named it this way to have continuity between this and the previous equation) My problem is with the heat. Assuming that all the difference in kinetic energy goes into producing heat (instead of other things as sound, etc.) then, since the initial and final kinetic energies differ: KE (initial) + A = KE (final) → A=ΔKE. I think this energy A is converted or manifests itself as heat instead of kinetic energy (assuming 100% efficiency), but how do I calculate the temperature? From the formula ΔT=Q/(mc) but that is assuming a uniform material; the object is made of different materials. Please give me some tips/pointers. Thank you for reading, and let me know if you want me to clarify anything. Have a nice day. [/QUOTE]
Insert quotes…
Post reply
Forums
Homework Help
Introductory Physics Homework Help
Change in temperature after an inelastic collision
Back
Top