# Pulley and Mass on an Inclined Ramp

1. Jun 21, 2009

### theuniverse

1. The problem statement, all variables and given/known data
A 20 kg mass is released, and the 5 kg mass on the ramp slides up the ramp from rest. As soon as the 5 kg mass gets to the end of the ramp, the string breaks down. What's the tension of the string?

http://img10.imageshack.us/img10/7603/figure1w.th.jpg [Broken]

2. Relevant equations
I would use:
Fg=mg
Fnet = Fg1 + Fg2 + Ff
Fnet = ma
Fk = (uk)(Fn)

The question provies distances too, but I am not sure whether I actually need them...

3. The attempt at a solution
First I found the weight of both masses using Fg=mg
M1(on ramp) = 49N
M2 (hanging) = 196N

Then I found the components of Fg (and thus Fn), as shown in my diagram.
Fn = 42.4N
Therefore, using Fk = (uk)(Fn), I found the friction to be -11N.

I know that I have to calculate Fnet. So: Fnet = 196N -24.5N +11N = 182.5N
*Note: I am not very sure what sign does the friction have in this problem...

Not sure how to find tension from here... Fnet = Ft + Fgx + Ff?

Last edited by a moderator: May 4, 2017
2. Jun 21, 2009

### Staff: Mentor

I recommend that you write separate force equations for each mass, then combine them. For the mass on the incline, consider forces parallel to the incline.

3. Jun 21, 2009