# Find acceleration only given distance of slop and angle of elevation.

1. Jul 14, 2007

### avsj

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?

2. Jul 14, 2007

### Staff: Mentor

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.

3. Jul 14, 2007

### robphy

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] ]

4. Jul 14, 2007

### avsj

Thanks Doc Al :D