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avsj
Jul14-07, 05:50 PM
1. The problem statement, all variables and given/known data

A puck is let go on the top of a frictionless slope. The slope is length .74 m and 3.5 degrees above the horizontal. What is the acceleration and how long does it take the puck to go down the slope?


2. Relevant equations

Fnet=ma
Fg=mg?


3. The attempt at a solution

If I was given m, I could just draw a free body diagram and find Fnet down the slope and then use m to find acceleration using Fnet=ma

Without mass, I am quite lost? Can it be done?

Doc Al
Jul14-07, 06:00 PM
You don't need a specific value for mass to draw a free body diagram--just call it "m". Hint: Perhaps the answer doesn't depend on m. :wink:

robphy
Jul14-07, 06:01 PM
Although you're not given an explicit value for m,
can you attempt to solve the problem assuming a nonzero value for m?
If you can, you might see why an explicit value wasn't given.

[ doh.... i hesistated too long [by rereading my post] o:)]

avsj
Jul14-07, 07:50 PM
Thanks Doc Al :D