Saturday, October 29, 2011

uTexas HW7 #18

I got question 17, but I don't see how we're supposed to find the maximum compression without knowing the spring constant. Can anyone help me out?

3 comments:

John said...
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John said...

1)Find the force of friction with Ff=µ(kinetic)mg.

2)Since energy is conserved, the total energy before the collision [0.5mv(initial)²] equals the energy lost to friction (µmg*2x) plus the final energy of the block [0.5mv(final)²].
Note that the reason why energy lost to friction uses 2x instead of x is because the block has to cover that distance twice, once while it is compressing the spring and again while the spring is extending to give the block its final energy.

3)Since you have the total energy lost to friction (ΔK or your answer from #17), just solve for x with ΔK=µ(kinetic)mg*2x.

CianC said...

Thanks!