physucks help

[b*rizzle]

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Okay guys -- see if you can get an answer that makes any kind of sense:

A hockey puck slows from 45 m/s to 44 m/s as it slides 25 m across the ice.
(a) What is the coefficient of kinetic friction between the ice and the puck?
(b) If the puck slides another 25 m, is its speed reduced to 43 m/s, more than 43 m/s, or less than 43 m/s? Explain

I know we have a few physics buffs here.

I figured out the coefficient of kinetic friction but my answer to part b is greater than 43 m/s. This intuitively doesn't make any sense to me.

(I used equations W= change in kinetic energy and Fd = W, where F is the force on the puck due to friction, and the force is equal to the coefficient of kinetic friction times the normal force).

 

[Superflyjsc]

i think u need the weight of the puck to solve for coefficient of friction.

v^2(final) - v^2(initial) = 2ax
N = mg

a = uN

u=a/N

 

[b*rizzle]

i think u need the weight of the puck to solve for coefficient of friction.

v^2(final) - v^2(initial) = 2ax
N = mg

a = uN

u=a/N

You shouldn't. If u set work (Fd, where F=uN=umg) equal to change in kinetic energy of the puck (.5mvf^2 - .5mvi^2), mass cancels out.

I have an answer. It just doesn't make any sense

 

[ZpackSux]

Isn't this a pharmacy forum

Take it to the Physics Board

 

[b*rizzle]

Isn't this a pharmacy forum

Take it to the Physics Board

Pre-pharmacy is for advising/etc.

I am asking our fellow SDNers to advise me on how to work this problem so that I may satisfactorily complete my pre-pharmacy requirements. 😛

Oh yeah and a few of these, in traditional Zpack style:

 

[ZpackSux]

Pre-pharmacy is for advising/etc.

I am asking our fellow SDNers to advise me on how to work this problem so that I may satisfactorily complete my pre-pharmacy requirements. 😛

Oh yeah and a few of these, in traditional Zpack style:

Dang..I've become predictable.